proper prop installation

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 .

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.

eric lavine wrote: 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

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!

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

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.

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

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?

C-Bass wrote: 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.

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

mrwillya wrote: Can you think of anywhere local I can find that? If I can't find a local one, would it be fine to run with my old one? Thanks

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.

Bri892001 wrote: 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?

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!

TX Foilhead wrote: 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.

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

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.

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.

Welcome aboard!

8122pbrainard wrote: slob02 wrote: 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?????? Give the lapping and install procedure a try. Your friends should too. I guarantee if done correctly you will not have a loose prop!

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.