proper prop installation
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=12866
Printed Date: April-26-2024 at 1:24am
Topic: proper prop installation
Posted By: 8122pbrainard
Subject: proper prop installation
Date Posted: February-14-2009 at 4:39pm
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The topic comes up frequently on the proper method of installing our props. We have even heard of people loosing brand new ones because they weren't installed properly. We are also seeing new CNC machined props come through with recommendations to lap the prop to the shaft. This I feel is due to the machined finish on the tapered bore rather than a reamed finish. Since I had my X55 hanging in the shop, I thought I'd take a few pictures and go through the steps.
Keep in mind that our props are held on by a close fitting taper. According to one of the prop manufacturers, 70% of the torque is said to be transmitted through this fit and the rest is the key/keyway. I personally feel it's 100% because the taper fit shouldn't slip at all. I've seen some pretty sloppy keys with 0 evidence that any force has been applied to them. Prop removed: 
Lightly clean the shaft with some emery paper or a Scotch brite pad: (If you don't have a new prop, clean the bore of it too) 
Here's what you'll need. High spot blue (Prussian blue) and valve grinding compound: 
Put a light coating of the blue on the shaft taper area: 
Put the prop on the shaft and rotate back and forth in a small arc. Remove the prop and take a look at the blue: 
You'll notice any high spots as lighter areas of the blue. This shaft, I made myself in the lathe about 20 years ago when I put a new bottom on the boat. The prop hasn't been off since then. (I know where all the rocks are on my lakes!!!) The prop is the original (64) to the boat. The taper fit isn't that bad considering it wasn't ever lapped in. Spread some valve grinding compound on the shaft: 
Put the prop on the shaft and with forward pressure on the prop, start turning it back and forth and rotating in 60 degree increments. When the compound seems to smooth out (no grit) pull the prop back and then forward again to get the compound re distributed. Rotate again. Repeat several times until there isn't much "grit" left to the compound. 
Blue again and put the prop back on to check the lapping. High spots removed: 
If not, repeat the lapping again. Your shaft and the bore of the prop should have a real nice and even mat finish on it. 
Clean all the compound and blue off with some solvent. Fit the prop to the shaft without the key and mark the forward position of the hub with some tape: 
The tape is a indicator that when you put the prop on with the key that it's forward against the shaft's taper. A common problem is that if the key is cocked or not in it's proper place, the prop will bottom out on the key rather than the taper. If you are using a new key, it may need to be fitted. If too wide, drag it across a flat file: 
Wrench: 
Now, if you can't tighten the castle nut up to the point of getting the cotter pin into the hole, you can actually back off the nut to the hole. Tightening the nut has seated the prop on the taper and remember it's the taper that holds the prop on. It's the reason a puller is needed to break them loose. Anyone who is able to remove a prop with a hammer and a block of wood has a problem!! BTW, every once in awhile, someone asks "why can't I grease or Never-Seize the taper so my prop will come off easier!! Well, you now know why and the correct answer is to tell them to get a decent puller! John, Did you notice only my right cuff shows up in the thread. I was real careful after you've given me such a hard time!!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Replies:
Posted By: saffer
Date Posted: February-14-2009 at 10:07pm
awesome awesome awesome
cant wait for the 542 now baby. Explain key installaton a bit more please ------------- If you can't be rich, you gotta be clever!  Wonder if I'm either right now.
http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 - My 88 2001 http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 |
Posted By: 8122pbrainard
Date Posted: February-14-2009 at 10:31pm
Key fitting: New keys are usually on the large side by a couple thousand (.002") and key ways may be slightly under width. File the sides until the key fits in both the shaft and prop. You shouldn't have to hammer it it but it also shouldn't be falling out. Key position: If the key is placed too far forward on the shaft, it can get into the area of the shaft where the keyway gets shallower caused by the radius of the milling cutter. This makes the key ride high causing the keyway on the prop to bottom out on the key and not the bore taper. This is why you want to keep a eye on the tape on the shaft. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
saffer wrote:Posted By: Riley
Date Posted: February-14-2009 at 10:33pm
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That's excellent Pete.
We ought to have a tech section for stuff like this. How much distance can be between the strut and the prop? ------------- |
Posted By: saffer
Date Posted: February-14-2009 at 10:35pm
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We ought to have a tech section for stuff like this- agreed
Is the key then suppossed to fit exactly under the prop and not stick out fore and aft? ------------- If you can't be rich, you gotta be clever! Wonder if I'm either right now.
http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 - My 88 2001 http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 |
Posted By: LaurelLakeSkier
Date Posted: February-14-2009 at 10:42pm
| The key can't go to far forward due to the taper at the end of the keyway. It also should not be so long that it will overhang the prop....this will interfere with the nut being tightened. |
Posted By: 8122pbrainard
Date Posted: February-14-2009 at 10:47pm
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Bruce,
The rule of thumb is 1 to 1&1/2 the diameter of the shaft between the strut and prop. It may vary due to the depth of the taper machined into different props. Kimbrian, The key can't stick out aft of the prop because that's where your prop nut goes. Forward it can be longer as it doesn't hurt anything as long as it doesn't ride up in the shallower keyway area. If you want, cut the key length to the same length as the prop hub. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: saffer
Date Posted: February-14-2009 at 10:53pm
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I got it now.
Thanks guys Keit-this site rocks man!!- gonna put many a mechanic out of business with my knowledge one day and work on my own stuff eh.  ------------- If you can't be rich, you gotta be clever! Wonder if I'm either right now.
http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 - My 88 2001 http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 |
Posted By: saffer
Date Posted: February-14-2009 at 10:55pm
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whilst im here, as you can see the pic on my entry is not a 88 SN, i somehow got this guys boat on but I cant edit it off.
HAve asked under general discussion for help but no help as of yet. Any ideas? ------------- If you can't be rich, you gotta be clever! Wonder if I'm either right now.
http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 - My 88 2001 http://www.correctcraftfan.com/diaries/details.asp?ID=3030&sort=&pagenum=8&yrstart=1988&yrend=1988 |
Posted By: Tim D
Date Posted: February-15-2009 at 12:32am
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Pete, I think spinning the prop in the water is going to seat the prop further on the taper, a lot more than tightening the nut against the prop. ------------- Tim D |
Posted By: 37N122W
Date Posted: February-15-2009 at 3:48am
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Great info! I'm about to change props on my boat and I had no idea about lapping and what not. Thanks! This site rocks!
JJ ------------- "It never gets easier, you just go faster." Greg LeMond |
Posted By: eric lavine
Date Posted: February-15-2009 at 12:12pm
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too add on such a great topic on how importanat keyed tapers are, on larger transmissions the "BullGear" which usually are the output gears and weigh about 400 lbs do not use a key, it is simply a keyless taper and you advance the gear on the shaft and the fit relies on the close tolerances of the 2 tapers, the transmission will use an 8" shaft, so you can imagine the torque going through the taper's and they dont spin on the shaft, fortunately these shafts have keys and you still have to advance the prop on the shaft and as Pete states the tapers need to be free of blemishes and the more contact the better of the surfaces ------------- "the things you own will start to own you" |
Posted By: Clew In
Date Posted: February-15-2009 at 12:59pm
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Hey 8122pbrainard,
Great write up and thanks for taking the time to put that together. I have a few more questions: One side of my key has rounded edges, what is that for and which way should it go? What kind of solvent should I use? What do you think about the castle nut vs. the nylock nut? I was talking to Skidim and they were recommending the Nylock nut. I am thinking I like the castle nut and cotter pin. Clew In ------------- Clew In |
Posted By: 8122pbrainard
Date Posted: February-15-2009 at 1:19pm
Check both the keyways cut in the prop and the shaft and see if ether have slight chamfers in the bottom corners. That's where the rounded edges of the key should go. If you are talking about chamfered ENDS, then that side goes in the shaft. Any strong solvent will cut both the blue and the valve grinding compound. I always have a gallon of both acetone and toluene in the shop. The toluene is actually better because it doesn't evaporate as fast. Ether the castle nut or the Nyloc do the job. However, Nyloc's are recommended for only one use. You already have the cross drilled hole for the cotter pin so I'd stick with it. If you do use a Nyloc, NEVER use a stainless on the stainless shaft. The combination is known to gall and lock up the threads. I've had to cut a stainless Nyloc off and then chase all over the northwoods of Wisconsin to find a 3/4-10 die to chase the threads!! Hopefully Skidim wasn't recommending the stainless Nyloc. If so, chalk one up against them!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: February-15-2009 at 1:27pm
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much to my amazement, i have a 3/4-10, i called and called looking for one, and i had one in my tool box, where it came from i dont know. ------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: February-15-2009 at 1:33pm
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Pete, can we use a block of wood between the hull and the prop blades to tighten? or even a pipe wrench on the shaft so it wont spin? ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: February-15-2009 at 2:04pm
Eric, You've brought up one valid point regarding the block of wood. (guys - The other with pipe wrench is a joke) I've seen the block of wood used by many people. I've done it myself just for a little extra leverage but great care must be taken. I know you recommend against it. The Nybral prop is tough. The prop blades must be able to take the torque of the engine which typically is around 300 ft. lbs. or better divided by 3. With reduction trans's, this is multiplied by the ratio. What I'm saying is it would take quite a lot of force on the wrench (probably with a cheater on it) to distort a prop however, I don't recommend the block of wood simply because I don't want someone to have a problem. Everything has a breaking point. A proper fit on the taper doesn't really need that much force to seat it. Give me a break - a pipe wrench!! I shutter when I see one of our maintenance guys with the channel locks!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: February-15-2009 at 2:18pm
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can i run the nut on with an impact? ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: February-15-2009 at 3:24pm
Sure - you know the factory does. They sure don't lap the props on. The impact is called "form the prop bore to the taper with force". Not enough torque? Get one of these: 
------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: February-15-2009 at 3:50pm
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Pete, i use the block of wood and an impact, sometimes things get taken out of context, if you tell the guy's a block of wood between the hull and blade you know damn sure they will have a big cheater pipe on the end of the cresent wrench jumping on it to get that last turn. One place that i do put put never sieze is between the nut and the prop contact surface, it allows a tighter turn with less force and wont gall the faces ------------- "the things you own will start to own you" |
Posted By: Clew In
Date Posted: March-04-2009 at 8:57pm
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Hey 8122pbrainard,
I received my Acme 540 today and I will try to put it on soon. Thanks again for the details they will come in handy and are much appreciated. Thanks, Clew In ------------- Clew In |
Posted By: anthonylizardi
Date Posted: March-04-2009 at 9:45pm
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Excellent, I did the lapping compound and got a nice surface but I wish I have know about the Prussian blue. We need to move this thread to the commmon questions asked.
Excellent, Thanks!! |
Posted By: Clew In
Date Posted: March-04-2009 at 9:54pm
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Hey,
I agree with you and maybe even add an installation procedure heading. When someone puts up an informative procedure it could live there and not get lost in the threads. Any way thanks again to all the experts giving us helpful advice. Clew In ------------- Clew In |
Posted By: Waterdog
Date Posted: March-06-2009 at 1:33pm
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Pete,
Nicely done! Thanks. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: Carl
Date Posted: March-09-2009 at 10:29pm
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When lapping a nibral prop on a stainless shaft, doesn't the prop lose most of the material?
Couldn't that be a problem? I'll be installing a new ACME in a few days. Good write up. |
Posted By: 8122pbrainard
Date Posted: March-09-2009 at 10:54pm
The Rockwell is close depending on the alloy of the shaft. I think you'd be surprised on how hard the nibral is. I Rockwelled a Acme 540 not too long ago and actually posted it. I see if I can find it because I forgot what the 540 turned out to be!! So, what are you worried about? We are not talking about removing large amounts of metal. Probably no more than .003". The prop shop will ream lots more when they do a prop rebuild. Don't lap it in and you will run the risk of loosing more that a couple thousand on the taper. Edit: I found it! The Nibral is a 78 on the B scale. That's getting up there and damn close to most stainless used on prop shafts. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Carl
Date Posted: March-09-2009 at 11:10pm
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Not really worried about anything. I was just initially surprised to see you using the prop to lap it with.
It makes sense now that I think about it, your trying to make the two pieces the same shape. They're close already so it shouldn't matter much which one loses the material. And a small amount of material also as you point out. |
Posted By: jbear
Date Posted: March-10-2009 at 12:12am
First of all...very good thread...just like we would expect from a guy of your talents Pete. The prop is off the '80 right now as I hit something coming out of the Glen a couple weeks ago. Eddie is checking the alignment for me as I had never tried to check it. Not as easy as you guys make it sound. Glad to have a friend like Eddie. Second...you gotta be the only guy I know that would work on his boat in a white shirt. You know I was looking just as soon as I saw the first picture with your hand in it. You know what I was hoping to see just so I could point it out. But you saved me the troubljohn ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: Clew In
Date Posted: March-22-2009 at 2:01am
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Hey 8122pbrainard,
I put my Acme 540 on today and everything went great. I had a little trouble finding the high spot blue. No auto stores have it and only two Napa stores in the Atlanta area had it. When I finished putting the castle nut on and installed the cotter pin the thing looks like a butterfly on the end of the shaft. I just cannot get it to wrap tight around the nut. Do you know any tricks to wrap it tight to the nut or does it even matter? Clew In ------------- Clew In |
Posted By: 8122pbrainard
Date Posted: March-22-2009 at 10:35am
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Tom,
The cotter legs get bent fore and aft and not radially around the hex of the nut. So, the "head" of the cotter sits all the way into one of the groves in the nut, one leg gets bent over the end of the shaft then the other you can trim shorter so it just gets bent forward over the nut. I guess I stopped short with my install and should have included a picture! Later! Don't worry if the cotter isn't tight. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: TX Foilhead
Date Posted: March-23-2009 at 12:57am
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I also had a problem finding the Prussian Blue, I guess nobody sets up gears properly anymore. I tried 3 NAPA's in a 30 mile radius of home. I ended up using a wide sharpie and some break cleaning fluid. I got the recipe off of a machinists forum, and then added a squirt of penetrating oil to keep it from drying out so fast. I just filled the cap of the sharpie about half and half with each and dipped the pen in it. After talking with some people who use the real stuff regularly I found out that Prussian Blue is basically a thin non-drying ink, so that's what I tried to make.
Not a perfect solution, but it saved me 3 hours of driving, and maybe it will help someone else out. OK flame away, I'm getting used to it. Don |
Posted By: Carl
Date Posted: March-23-2009 at 1:12am
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Also found nobody had the Prussian blue in stock.
Graingers had "Hi-spot blue" which seems to be the same thing. I'll be using it in a week or two and will report back. About $6 per tube. |
Posted By: Luchog
Date Posted: April-17-2009 at 12:07pm
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I will try to get pics later, but my nut tops on the key no the prop, wich fits tight.
But I sense I did not do something right when I installed it (like 100hs ago) ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: 8122pbrainard
Date Posted: April-17-2009 at 3:41pm
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Luciano,
If the prop nut is bottoming out on the key and the key is as far forward as possible then the key needs to be shortened. Be carefull that the prop is sitting on the shaft taper and not on the key. Dry fit the prop without the key and mark it's forward position with the tape on the shaft to make sure. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: lonestar
Date Posted: April-18-2009 at 3:03pm
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Ok, so last fall when I removed my prop to have it serviced I was able to bump my hand on the back of it and pop it off. Im guessing thats a problem but what should I be looking for ? I actuallly just put the refinished prop on ten min ago but I havent tightend it down yet. ------------- lonestar |
Posted By: 8122pbrainard
Date Posted: April-18-2009 at 3:23pm
The high spot blue tells you the high and low spots of the taper in the middle back or front. If you were able to remove the prop by hand then ether the taper needs lapping or the prop wasn't installed properly. The most common problem on a improper install is the prop bottoming on the top of the key and not the taper. Use the dry fit and masking tape trick as mentioned. Did you by chance have the prop serviced last fall due to vibration? You really should lap on this prop as your taper may now be bad due to running a loose prop. Did the prop shop check the taper? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: lonestar
Date Posted: April-18-2009 at 9:34pm
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I realy dont know if they would have done anything with the taper. I just saw some dings in the prop and thought it a good idea to get it serviced and get a fresh start to the season. I took over looking after this boat last summer after it had been unused for several years. Im not an expert but I would say the maint program was lacking at best. If I were to guess the prop has not been off since new and its an 1988. One thing I did notice is there is a very small amount of play in the drive shaft, I dont know if that would mean anything ? ------------- lonestar |
Posted By: martin 74
Date Posted: August-07-2009 at 4:35pm
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I used this excellent post by Pete from last spring to properly install my prop after it had been repaired by Delta. You probably won't be able to find the blue High Point but per Pete it's optional, I didn't need it. My key moved easily in the keyway and I was able to push it back with the cotter pin so the prop wouldn't tighten on it. I torqued my prop to 30 lbs per Acme. I tightened it as I could holding the prop with my hands, in my case, be sure to press it on well, it shouldn't move or jiggle at all on the shaft. To remove my prop I ordered an Acme harmonic prop removal tool ($30) and stainless cotter pin from Delta. I got it in two days and used the CCF discount. The prop took a week to fix and one week round trip with UPS. (two weeks total) I was a little worried about using the harmonic prop removal tool but it worked great. Be sure not to tighten it all the way against the prop and it comes off with a few sharp wraps. Hope this helps someone now that it's peek prop repair time. Here are the before and after repair pics of my prop.
Rich ------------- |
Posted By: C-Bass
Date Posted: August-07-2009 at 5:33pm
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Not seeing any pics Rich... ------------- Craig 67 SN 73 SN http://www.correctcraftfan.com/diaries/details.asp?ID=6103" rel="nofollow - 99 Sport 85SN |
Posted By: martin 74
Date Posted: August-07-2009 at 6:17pm
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Sorry, here they are.
Rich 
 ------------- |
Posted By: slob02
Date Posted: August-30-2009 at 12:14am
| I have had 3 nautiques and have had friends with many and I have never seen one stay tight on the taper after hitting reverse. Not saying it shouldn't though. If you keep it on a trailer, the last thing you do is accelerate forward to get it on the trailer (tight on the shaft) . If you put it on a boat lift, the last thing you do is hit reverse (pulling away from the shaft). I just don't know if it is something I should worry about or not. I too would think it should be tight on the shaft........but of my 93,95, and 97....and a friends 92, 97, and 98...none have stayed tight after hitting reverse?????? |
Posted By: 8122pbrainard
Date Posted: August-30-2009 at 1:05am
Give the lapping and install procedure a try. Your friends should too. I guarantee if done correctly you will not have a loose prop! Your tapper is off or your key isn't in the proper position not allowing the prop to seat on the taper. Keep in mind that a taper is the only thing that holds a drill chuck in a drill press spindle!! Also, take note of Eric's comment that many trans components are held together with tapers only. No nuts!!! Think about why a puller is needed to get a prop off!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: BuffaloBFN
Date Posted: August-30-2009 at 11:03am
Pete's right. If you follow this procedure the only thing that will be loose is the cotter pin and it shouldn't be very loose(slight pivot). I think the castle nut or nylock is a formality when the taper is right. ------------- http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO |
Posted By: slob02
Date Posted: August-30-2009 at 12:11pm
| I will give it a try and let you guys know how it goes! I never really felt 100% about it before, but could never understand why so many are loose after hitting reverse. I have lapped primary clutches on snowmobiles to get that good clean fit and will give it a try. |
Posted By: BuffaloBFN
Date Posted: August-30-2009 at 12:15pm
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Welcome aboard! ------------- http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO |
Posted By: horkn
Date Posted: July-01-2010 at 2:03pm
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So I see martin74 used the harmonic prop puller. Any thoughts on these? ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: drtybrdy9
Date Posted: July-08-2011 at 3:08pm
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Do the newer boats have the same taper that holds the prop on? I recently had a new prop put on the boat by the dealer, who is losing my confidence by the second, and have noticed some vibrations. After seeing this I think that might be the reason. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5402&sort=&pagenum=1 - 05 SAN Limited 210 |
Posted By: kapla
Date Posted: July-08-2011 at 3:20pm
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yes, unless you have a splined shaft end like some MC´s..not likely though...hahaha
------------- <a href="">1992 ski nautique |
Posted By: mrwillya
Date Posted: June-01-2012 at 1:50pm
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Old topic, I know, but I have a question on this process. I took off my nut and the prop fell right off, no puller no hammer. From what it looks like here, it should have been tough to remove due to good surface contact of prop on shaft (heh). I'll definitely be doing the Prussian Blue and compound to ensure it's a perfect fit. I'm replacing my stock 13x13 with an Acme 543. Should I be concerned about my key being worn down? Or anything else for that matter. |
Posted By: TX Foilhead
Date Posted: June-01-2012 at 2:08pm
| Get a new key, they're cheap. If the prop is on correctly it shouldn't be easy to get it off the taper, but if you hit or even tapped something with it that may have knoced it loose. The same idea behind using the prop ringer instead of a puller, the right vibration will shake it just enough to make it loose. |
Posted By: mrwillya
Date Posted: June-01-2012 at 2:12pm
Can you think of anywhere local I can find that? I'm looking to get on the water this weekend. If I can't find a local one, would it be fine to run with my old one? They are easy to find online! Thanks |
Posted By: Bri892001
Date Posted: June-01-2012 at 2:25pm
I'm sure you can reuse the old key if it's not damaged and time is a factor. 543? This is a Left hand rotation prop you know, right? |
Posted By: mrwillya
Date Posted: June-01-2012 at 2:31pm
Ha, yep, I'm a non-CC person right now. I just find this site has the most knowledgeable people concerning these type of boats. I'm the proud owner of a 1985 Ski Supreme which is LH rotation. Thanks for your help! |
Posted By: TX Foilhead
Date Posted: June-01-2012 at 3:05pm
Since I've never been to Iowa, not really familiar with what's local. Just a wild guess, but someone who sells farm implements ought to have one or a machine shop that works on those sort of things. (Think John Deere, not Tractor Supply). |
Posted By: 8122pbrainard
Date Posted: June-01-2012 at 3:23pm
A well stocked hardware or even a home improvement should have 1/4" x 1/4" brass stock. You may need to get a couple feet though. If not brass, go with stainless. Cut a piece and fit it with a file. You may still be able to use your old key. Turn it 90 degrees and see how it fits the keyway in the shaft and the prop. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: C-Bass
Date Posted: June-01-2012 at 6:14pm
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My prop on the 85' also fell right off. It wasn't seated at all. The new Acme was lapped in correctly though. Also...lets see some pics of that Ski Supreme. ------------- Craig 67 SN 73 SN http://www.correctcraftfan.com/diaries/details.asp?ID=6103" rel="nofollow - 99 Sport 85SN |
Posted By: mrwillya
Date Posted: June-01-2012 at 6:24pm
I have a couple pics in this thread. I won't post them here to refrain from clogging up this post! Great boat, I've done a ton of improvements. Come to think of it, I should update that thread with a few of the changes I've made since getting it. http://www.correctcraftfan.com/forum/forum_posts.asp?TID=22926&PN=1&title=ski-supreme-knowledge-base" rel="nofollow - http://www.correctcraftfan.com/forum/forum_posts.asp?TID=22926&PN=1&title=ski-supreme-knowledge-base |
Posted By: eric lavine
Date Posted: June-02-2012 at 10:22am
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pretty much, we will sweat the props on larger boats, Ive never practiced this in the past but it does seem logical, after its as tight as we can get the prop on with a hammer wrench, we will sweat the prop and now i gather what sweating the prop means, we slowly glaze starting at the blades to heat the prop and then to the hub, the bronze will actually start to sweat as its heated...when i say heat it, i mean flash heat not concentrated, at this point the nut will actually go another 1/2 to 3/4 turn...then it takes a puller to get the prop off. I did notice on some other boats in the yard that were not sweated and when removing the inner nut against the prop they would be loose because the prop would advance from thrust. ------------- "the things you own will start to own you" |
Posted By: TX Foilhead
Date Posted: June-03-2012 at 1:28am
| Correct me if I'm wrong Eric, by sweating the prop you are makink it expand to push it farther up the taper. If that's what's happening is it so important to lap it to the shaft? My thinking here is the leaping make the surface contact perfect, but that doesn't get it farther up the taper, sweating it will but is that a stronger connection in the end. Obviously it's best to do both, but which one is getting you more bang for the buck? |
Posted By: 8122pbrainard
Date Posted: June-03-2012 at 8:58am
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Don, The larger the prop is, the harder it is to psychically lap a prop. Imagine trying to handle a prop 3' in diameter or larger. Also, these are slow RPM props. They what them to stay on and within reason don't care about some balance/vibration issues. I'd sure stick with the lapping for a precise fit. You sure wouldn't want to take a CNC prop with all it's precision and distort it by a misfit taper. Keep in mine that I believe it was Acme that came out with the lapping recommendation with the advent of the CNC prop. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: June-03-2012 at 10:02am
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ah yes, lapping is also recommended, you want at least 80% contact on the surfaces and with blueing the prop is the method to determine the contact, once the contact is achieved then you want to advance the prop onto the shaft, really i was thinking about this and i dont see any reason why you could do the die procedure, lap it and then put the prop in the oven at 400 degrees and then advance your prop quickly. these props do spin engine speed or a tad less so getting it up on the shaft seated is important...thats me though. but never skip the fitting procedure which includes die and lapping it in, if i had the shaft out, which most of the time i did, I would dangerously put the shaft in the lathe and spin it slowly to lap the prop in ------------- "the things you own will start to own you" |
Posted By: TX Foilhead
Date Posted: June-03-2012 at 10:27am
| Pete, my thinking was that if they were roughly equal in effectiveness then it would give people another option if they could only do one and already had a propane torch. I agree its not a good idea to break out the acetalyne torch and heat your new prop until its almost molten so you can push it all the way to the strut. |
Posted By: 8122pbrainard
Date Posted: June-03-2012 at 11:45am
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Don, No problem with thinking of other ways to seat a prop but I'd stay with the lapping. Yes, I'd hate to see someone getting the prop too hot (heat and a slow cool anneals brass alloys). As Eric mentioned the "sweating" is the indicator of how hot you're getting the prop. A first timer may not catch on. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gmoney
Date Posted: June-03-2012 at 3:02pm
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Great thread. We have a brand new prop hanging on the wall, just in case. It will get lapped in for sure. GMoney ------------- "Hit it" |
Posted By: eric lavine
Date Posted: June-03-2012 at 3:11pm
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i always forget about the dummy factor lol, I really can picture now someone really heating up the prop, thats the reason i suggested 350 or 400 in the oven. really the combination of the 3, die lap and sweat, i would concur is probably the correct way to install a prop, in reality though i dont know how important it would be to sweat the prop at this point, obviously if you want it up on the taper this would be the way to do it ------------- "the things you own will start to own you" |
Posted By: mrwillya
Date Posted: June-03-2012 at 4:13pm
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Took the Ski Supreme out this weekend with the new ACME 543 and WOW what a difference! I didn't notice it until I was pulled behind it on skis. It almost pulled the rope out of my hand! I then had someone else drive and really felt the faster hole shot. I guess while I drove it it was tougher to notice the difference. Sounds odd, I know! Thanks for your prop help. |
Posted By: 8122pbrainard
Date Posted: June-03-2012 at 4:56pm
Eric, With the lap and sweat, you'll need one of these to get it off!!    I'd have to borrow our 55 ton from work!  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: March-02-2013 at 5:08pm
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New twist on an old subject: Does a prop need to be re-lapped when it goes on a different boat? I would think not, but maybe there could be a slight difference in taper. Pete - What do you think? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 8122pbrainard
Date Posted: March-02-2013 at 8:51pm
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Chris, I say yes since the whole idea is to precisely match the two tapers. Yes, machining is pretty accurate but I still suggest lapping. It doesn't take much for the tapers to be off .0005" over the length of the taper. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: March-02-2013 at 10:18pm
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Well, it looks some props are changing hands,. I am getting a used one myself. I'll do the lap just to be safe. Hopefully this thread will help others know about the technique. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 4mor
Date Posted: March-06-2013 at 12:42am
| Wow!! Never knew that mounting a prop could be so complicated. My '66 S-N came with a bronze prop. At the time, I bought a spare since my boat (and my roommates boat) were to be used by various ski clubs in Florida for their tournaments. I have interchanged the two props at least a dozen times over the past 48 years and in all that time, I have never "blued" the shaft or for that matter, even cleaned it. Am I doing something wrong or am I just lucky . |
Posted By: 4mor
Date Posted: March-06-2013 at 12:43am
| Wow!! Never knew that mounting a prop could be so complicated. My '66 S-N came with a bronze prop. At the time, I bought a spare since my boat (and my roommates boat) were to be used by various ski clubs in Florida for their tournaments. I have interchanged the two props at least a dozen times over the past 48 years and in all that time, I have never "blued" the shaft or for that matter, even cleaned it. Am I doing something wrong or am I just lucky . |
Posted By: 8122pbrainard
Date Posted: March-06-2013 at 9:19am
Blueing is an option. It's just an indicator of high and low spots. It's the lapping that is key to matching the taper. Yes, many have gotten away without lapping. Most have been lucky but there are others who have lost props. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: kapla
Date Posted: March-06-2013 at 12:03pm
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Tell me, lost the cstle nut and the prop remain on its place! Good i followed this instructions ------------- <a href="">1992 ski nautique |
Posted By: lewy2001
Date Posted: March-06-2013 at 8:50pm
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Fitted my new 1442 the other day. Checked it with blue compound almost perfect contact on taper. Still gave it a quick lap with the cutting compound. ACME are now putting a note in with their props to check the taper fit.  ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: Bones71
Date Posted: June-11-2013 at 7:13pm
| Guys, if I can't find Prussian blue what else could I use? I know they can get it for me but is there another product I could use? Thanks, Tony. |
Posted By: baitkiller
Date Posted: June-11-2013 at 8:15pm
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Tony, I have found my own blood to be a suitable substitute... It has gotten a little thinner after 30 years in S Florida and seems to flow nicely over machined surfaces... ------------- Jesus was a bare-footer............. |
Posted By: Bones71
Date Posted: June-11-2013 at 8:24pm
| Been there. I went to Napa and I'll get the Prussian tomorrow. I thought I would have to wait. Thanks, Tony. |
Posted By: SNobsessed
Date Posted: June-11-2013 at 8:46pm
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Tony - The grinding compound leaves a satin finish. I have not used the blue. I think the bogey is 90% cleanup. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: gR@HaM
Date Posted: April-30-2014 at 7:11pm
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Old thread I know, but couldnt see any mention of checking for flat spots on the prop taper? It's taken me a considerable amount of lapping and am currently at ~95% contact with the prop. The shaft taper is spot on.. ------------- '82 Ski Tique |
Posted By: baitkiller
Date Posted: April-30-2014 at 7:15pm
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95%? Bolt it up and splash the damn thing already! ------------- Jesus was a bare-footer............. |
Posted By: IAughtNaut
Date Posted: April-30-2014 at 7:16pm
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You're probably good...there's a lot of guys who have never lapped a prop and never have any problems. You hit the toilet 95% of the time and your toes are going to stay pretty dry. ------------- bring the ruckus http://www.correctcraftfan.com/diaries/details.asp?ID=5347" rel="nofollow - 2000 Pro Air |
Posted By: gR@HaM
Date Posted: April-30-2014 at 7:29pm
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Thanks fellas its getting there slowly ------------- '82 Ski Tique |
Posted By: gR@HaM
Date Posted: April-30-2014 at 7:37pm
Shaft looks good http://s258.photobucket.com/user/graham22k/media/Mobile%20Uploads/20140430_210737_resized_zpsecb3caff.jpg.html" rel="nofollow"> flat spot on prop http://s258.photobucket.com/user/graham22k/media/Mobile%20Uploads/20140430_211543_resized_zps179dd412.jpg.html" rel="nofollow">  ------------- '82 Ski Tique |
Posted By: 8122pbrainard
Date Posted: April-30-2014 at 8:57pm
Yes, there are plenty of people who have never lapped a prop but if you read this thread thoroughly you will understand that was with the old props and not the CNC machined props. Props used to be reamed but the CNC props are not. Yes, CNC is accurate but not to the extent of the greatest fit. Why do you think Morris tapers are ground? Why do you think Acme even recommends lapping. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: May-01-2014 at 11:10am
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Graham - My prop's taper (after lapping) looked exactly like what you ended up with. I got to the point of diminishing returns & just went with it. It hasn't come loose, been 5+ years. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: gR@HaM
Date Posted: May-01-2014 at 2:11pm
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That's good to know, thanks ------------- '82 Ski Tique |
Posted By: phatsat67
Date Posted: May-01-2014 at 2:31pm
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Both Acmes I have lapped had a run up the side. The line was uniform and they both stay on the taper just fine. ------------- |
Posted By: NCH20SKIER
Date Posted: May-04-2014 at 9:19am
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Suggestion - if your taking the time to lap the shaft above spend the extra bucks and get the correct sized wrench and sell the adjustable to those working on mastercrafts. Got to say I was very surprised to see such a tool in Pete's hand ------------- '05 206 Limited '88 BFN |
Posted By: Russman
Date Posted: May-16-2016 at 11:58am
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there is another thread on dumb things said about boats. Well!, I have potentially a dumb question on this topic. I went to NAPA and had to order the Prussian Blue and the Valve Grinding Compound. When I did i was asked (Water or grease base) then was told that the grease was no longer available. So, the question I have is "is the water based Valve Grinding Compound effective for the lapping prior to a new prop install.?" Thanks for you response. ------------- 1989 2001 SN / Prior 1978 Cobalt 18 |
Posted By: 8122pbrainard
Date Posted: May-16-2016 at 12:31pm
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Russ, Water base will work just fine plus it's easier to clean up! The Prussian blue is optional as it's just a good indicator of high and low spots. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Russman
Date Posted: May-16-2016 at 12:39pm
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Thanks, I was going to install yesterday, but when I went outside to head to the unheated barn I moved the boat to from heated storage it was way too cold and I decided that an inside the house job was in my interest. Warming up this week so I will get it then. ------------- 1989 2001 SN / Prior 1978 Cobalt 18 |
Posted By: Russman
Date Posted: June-15-2016 at 10:45am
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New 422 installed. I am glad that I decided to change the prop this year as when I went to change the screw was loose and the prop just fell off the taper. I am thinking that I am fortunate that I did not have any trouble last season. I lapped the shaft as mentioned in this thread and ended with a nice fit. Here is a pic, Cleanup of underside of boat is needed!!!!! I also need to do some serious trailer work in the fall.  ------------- 1989 2001 SN / Prior 1978 Cobalt 18 |
Posted By: TedR
Date Posted: August-16-2016 at 11:02am
| What a great and useful post Peter, thanks for all the info... |
Posted By: MrMcD
Date Posted: August-16-2016 at 2:29pm
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This is a fantastic and helpful thread for sure Pete, Very kind of you to share the knowledge with us clowns. I got away with not lapping for over 25 years but I now know that was wrong. One point on torqueing the prop nut. 30-35 pounds of torque is not very much. Even small cars torque the wheel studs to 90 pounds torque so keep in mind how little 35 pounds is. Most of us have changed a tire on our cars and know how tight that is. The prop nut is about 1/3 that tight. An impact gun could blast that nut down to 150-250 pounds in a quick application of air power. Using a 2x4 to tighten the nut? Any water skier has plenty of grip in your hands to hold the prop with one hand while tightening the nut to 35 foot pounds. If you need a 2x4 you are way too tight. Using a crescent wrench on the nut, if adjusted properly I see zero issue using the adjustable wrench for this little amount of torque. I should follow up with my observation, in the old days before lapping changing a prop was really easy. I never had to fight getting one off because they were installed badly and I did not know it. A lapped prop will need a tool to remove it every time, showing you did the job correctly and safely. I also had the clank of the prop hitting the nut when put in reverse before I started lapping, that clank going into reverse should be a red flag for any inboard boater. Pete"s advice should be listed as gospel on this issue. Thanks again and I hope all the new guys get a chance to read Pete's advice. |
Posted By: 8122pbrainard
Date Posted: August-16-2016 at 3:36pm
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Mark, Thanks for the compliment but I wasn't the one who started the practice. Notices came with the Acme CNC props recommending lapping. I simply did the pictorial thread. I mentioned it in the tread that I have a feeling the recommendation is due to the taper bore being machined and not reamed. The machining will leave a rougher finish than reaming but lapping will remove the roughness. The actual lapping practice has been with us for many years in the tool and die trade. In fact, Duane's old enough to have actually been involved with the lapping inception!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Duane in Indy
Date Posted: August-16-2016 at 4:22pm
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Pete, We used to lap horse shoes before the car came along. (BTW we are only about 2 years apart) ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: 8122pbrainard
Date Posted: August-16-2016 at 4:33pm
Duane, I knew I'd get you up from that afternoon nap! I've heard that lapping went back before the pyramids were built. Sand was placed between stones to be fitted together, then one was moved back and forth and the high spots would get ground off. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: TedR
Date Posted: August-16-2016 at 6:23pm
 Delta even threw in some gratis beer coozies! |
Posted By: geecee
Date Posted: November-30-2016 at 8:08am
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Just pulled my prop to have it rebuilt and after reading this thread realized it had a stainless nylock on, I did not have any issues taking it off, but when I reinstall I would like to get the right thing. What should I get if not stainless? ------------- 1983 Ski Nautique '2001' -Chev 350 Mercruiser -Custom Wake Tower -Custom Interior |