1979 SKI NAUTIQUE WILL NOT TOP OUT.
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=1541
Printed Date: November-22-2024 at 3:12pm
Topic: 1979 SKI NAUTIQUE WILL NOT TOP OUT.
Posted By: Guests
Subject: 1979 SKI NAUTIQUE WILL NOT TOP OUT.
Date Posted: April-26-2005 at 6:02pm
My buddy just bought a 1979 ski nautique with the 351 commander. It starts, idles, runs great until you try to push it past 28 mph. The engine starts to bog down and speed up. The speed doesn't drop off it just surges. We are new to inboards any help will be greatly appreciated. We think it might be some kind of fuel problem. We have replaced the fuel filter. We also installed a new vacuum line from the fuel pump to the flame arrester. The vacuum line was kinked at the fuel pump. It has been cold this week up here in Canada and have not yet had a chance to test our changes.
Thanks in advance
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Replies:
Posted By: nates78ski
Date Posted: April-27-2005 at 10:28am
Sounds like the secondaries of the carb are not working. First you need to check the choke and make sure it is fully opening.There is a secondary lock out if the choke does not open all the way. If thats ok then check the timing, the secondaries work on vacuum balance. Third check the throttle plates for binding. Then check the secondary vacuum diaphram for proper operation.
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Nathan
http://correctcraftfan.com/diaries/details.asp?ID=1463&sort=&pagenum=3&yrstart=1978&yrend=1978" rel="nofollow - My '78 Ski Nautique
<a href="http://photobucket.com/Nates78ski" rel="nofoll
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Posted By: David F
Date Posted: April-27-2005 at 3:58pm
BTW, the hose between the fuel pump and spark arrestor is not a vacuum line, but merely and means to get fuel that leaks past a ruptured diaghram into the engine to be safely burned off. The hose should be clear so you can visually see that you have a leaking fuel pump.
Symptoms seem to indicate fuel starvation, but can be many things including electrical like a weak coil. High load fuel starvation will drive you crazy thinking it to many other things, so kept it in mind. I once chased a similiar problem for years until I discovered that my in-line fuel filter had the wrong size hose clamp that let air past. The pump was sucking air and not delivering enough fuel to keep the carb fuel bowls filled. Good luck.
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Posted By: 79nautique
Date Posted: April-27-2005 at 4:10pm
I agree it is a fuel problem. So the first place is to check filters and lines for clogs or restrictions, then the next step would be to check the fuel pressure, then you need to check the carb and make sure the linkage is correct and the secondary diaphram is working correctly, then I would move to ignitions system.
I would bet that your problem is the fuel pump. Was there any fuel in the vaccuum line as you called it? if there was then you already found the problem and the fuel pump is bad.
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: Guests
Date Posted: April-27-2005 at 5:16pm
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Thanks guys for your suggestions. We are in a cold snap up here and won't be able to test it for about a week. I will let you know what we find and i'm sure we will have more questions. Does any one know what is the standard prop on this boat? It has a four blade which i am prity sure it is not original. What is the prop shaft dia. or how do we measure it? What is the max rpm? Thanks again guys for all the help.
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Posted By: Tim D
Date Posted: April-27-2005 at 6:38pm
I think the standard prop is a 13x13.
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Tim D
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