Ski Nautique 1979 Prop Question |
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Benni27
Newbie Joined: September-22-2014 Location: Germany Status: Offline Points: 12 |
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Posted: September-22-2014 at 7:52am |
Hey Guys,
I'm new in this Forum and read a lot of helpful things about my old Ski Nautique. It's a 1979 Ski Nautique with a OMC 350 (260hp) in it. Now I have a question about my Prop. Actually there is a 13RH14 on it, I hope you can see the Picture.. She ran max 4200rpm and goes max up to 68 kph, so I think that isn't enough for this Engine. What is the original Prop for this Boat and what kind of Prop ist good for Wakeboarding? I read a lot about ACME and OJ Props, but don't know which of them is the best for me. Thanks an greets from Germany Benni |
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Orlando76
Grand Poobah Joined: May-21-2013 Location: Mount Dora, FL Status: Offline Points: 3108 |
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Greetings to Germany. 4200 and 68 sounds a bit low to me. I have run 13x14 Federals on mine and turned better numbers. 13x13 Federal was the OEM prop but sometimes I wonder if correct craft might've sent a few boats out with 13x14. An Acme 540 (13x12) would be the correct replacement for the 13x13 Fed. You will be much happier with it. Prices range greatly online but I know shipping may be a curveball for you, best of luck.
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Morfoot
Grand Poobah Joined: February-06-2004 Location: South Lanier Status: Offline Points: 5310 |
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Benni welcome to CCFan first of all and lets see some pics of the 79 SN. Always cool to see pics of a new members boat and bonus points when it's a European member.
If wakeboarding is your primary use of the boat then I'd say you should go with the ACME 542. It's a 11.5 pitch prop vs. The 540 which is 12.0 so the hole shot would be a little better especially if your weighted down for boarding..You'll sacrifice some top end speed but that doesn't seem to be what your searching for. |
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"Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman"
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13510 |
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Benni, welcome! How about some more pictures of the boat? Have you had it a while? Seems to be a long shaft you have there. How is the rest of the drivetrain? Hate to see you invest in a new prop only to find other, possibly more expensive issues.
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skutsch
Grand Poobah Joined: June-19-2008 Location: Racine, WI Status: Offline Points: 2874 |
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I am also a little alarmed by the 4200 max RPM. When is the last time plugs were changed, cap and rotor and timing checked. Wow as Hollywood said, check out the prop, it is at least 2 inches from the strut, I don't think I have ever seen one like that - very interesting.
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hotboat
Gold Member Joined: March-28-2009 Location: Conn Lake Pa Status: Offline Points: 814 |
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Not uncommon in that era, mine had 2.25" from hub to strut, made an adjustable coupler and found midway to be best performance. A lot of them also got 13x14 props, it would be a good home for a 540 acme |
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Brian
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21107 |
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Agree with all of the above... 4200 is low and probably the result of the too-large prop. I would think that 4200 with a 13x14 would push you faster than 42mph though... So something is amiss. Either inaccurate tach, speedo (GPS?) or a worn out prop. Either way, 540 is the hot ticket and should allow the engine to turn in the sweet spot for best performance (4600-4800). A 542 on that hull should not be necessary unless you're running a LOT of weight, ALL the time.
Do take the opportunity to check out the rest of the drivetrain... 2" of prop to strut clearance is excessive, though not necessarily uncommon from the factory. If your shaft is half way out of the coupler, now would be a nice time to realize it! Keeping that clearance below an inch (ideally ~1/2") would be best if you end up replacing/repairing components. |
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Benni27
Newbie Joined: September-22-2014 Location: Germany Status: Offline Points: 12 |
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We (2 Friends and I) own her since Nov, 2013 and we know that there is a lot to do. Before the saison we changed Plugs, Plug Cables, Cap and Rotor. Didn't checked the timings, maybe it's time for. 1870 hours on her.
Now some pics :-): Ok, so I think the ACME 540 is a good choice. The Speed is GPS and the Antifouling is not in good condition, so it's possible that there are maybe 5kph lost because of the resistance on the Water (but what are 5kph? :-D). Next step is to check the timing and the shaft, or buy the Prop and wonder how fast this lady could go? |
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skutsch
Grand Poobah Joined: June-19-2008 Location: Racine, WI Status: Offline Points: 2874 |
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NICE looking Ski Nautique! Another Team Red boat!!! I am guessing that bottom paint is definitely NOT helping on the top speed thing.
Kristoff will have to let us know if Mann Filters are better then Fram!!! (Benni27 - thats a joke you will learn to understand, the topic of oils and oil filters become pretty contested around here - HA!) |
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Benni27
Newbie Joined: September-22-2014 Location: Germany Status: Offline Points: 12 |
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Haha okay :-D, that Bottom Paint is on the To-Do-List for this Winter...
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Morfoot
Grand Poobah Joined: February-06-2004 Location: South Lanier Status: Offline Points: 5310 |
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Go TEAM RED!
Yes, that bottom paint can't be helping your speed and you need to get a timing light on it and double check your points gap. Digging the wacky extended pylon paint scheme...Groovy baby Yeah! |
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"Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman"
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storm34
Grand Poobah Joined: November-03-2008 Location: Dexter Iowa Status: Offline Points: 4492 |
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Upside down valve cover is good for atleast -2mph as well.
Welcome to the site! |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Maybe not Chris - It's a RH engine so you need to be able to read the text from the starboard side. Nice boat, what lake are you on? |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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Benni27
Newbie Joined: September-22-2014 Location: Germany Status: Offline Points: 12 |
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I'm on Lake of Constance in Germany..
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Benni27
Newbie Joined: September-22-2014 Location: Germany Status: Offline Points: 12 |
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Hey Guys,
today I checked the timing and set it to 8° after OT, this is where she ran's ok (without gear fires up great, in gear max 3900-4000) What is the correct timing for the OMC 350? There is a Petronix Ignition: |
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Donald80SN
Grand Poobah Joined: January-12-2009 Location: Denver, NC Status: Offline Points: 3887 |
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Top speed should be about 46 MPH. Your chevy might use to do a little more. At a CCFAN event, the guys moved my timing to 10 or 11 degrees. I have a 351 Ford W in my boat. My 80 has a 13 x 13 prop. You can get a better price from Delta Prop on that 540 ACME. They are a site sponsor and there is a CCFAN code to save you some money. I believe that it is 10%.
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baitkiller
Platinum Member Joined: October-11-2011 Location: SW Florida Status: Offline Points: 1693 |
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Too much prop for sure. The bottom paint wont be a measurable difference on this class of boat, just fugly.
My 350 Chevy on a 1979 SN is making about 280 or so ponies and I run a 13 / 12 ACME to 4850 and 49 MPH (gps) with the final timing set pretty conservative at 10* initial and 28* full advance. Left hand though... Im a bit baccereds. |
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Jesus was a bare-footer.............
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