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1993 PCM 351 Gas leaking into Crank Case

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Printed Date: December-28-2024 at 2:39pm


Topic: 1993 PCM 351 Gas leaking into Crank Case
Posted By: Casey Buck
Subject: 1993 PCM 351 Gas leaking into Crank Case
Date Posted: June-27-2012 at 5:18pm
Any idea's on what can cause this problem? I've checked the floats in both carb bowls and they seem to be working fine. I've read that the marine fuel pump is designed to prevent this from happening if it fails but I havent gotten that far yet. Any help or suggestions will be greatly appreciated. Thanks!



Replies:
Posted By: Jllogan
Date Posted: June-27-2012 at 5:21pm
when you shut off your engine, does the carb drip? How do you know you are getting fuel in the crankcase? Oil smell like gas?

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http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001





Posted By: Casey Buck
Date Posted: June-27-2012 at 5:50pm
Yes, the oil smells like gas. I did have a leak on the fuel line where the line enters the carb but when I shut the engine down, it stopped leaking. Also for the brief time I ran the engine, the engine was blowing greyish white smoke out of the exhaust similar to the smoke I've seen previously from a burnt water pump impeller.


Posted By: Jllogan
Date Posted: June-27-2012 at 5:53pm
well gas must be pouring when the boat is shut off and flooding it then leaking down into the crankcase. Look down the carb after you shut it off and see if its dripping. The needle and seat may need replaced if you feel the float is adjusted properly.

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http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001





Posted By: Casey Buck
Date Posted: June-27-2012 at 6:04pm
I've taken the carb off and checked the needle and seat. It looks good too. I even had a mechanic friend of mine who is pretty much an expert on Holley carbs to check behind me and he found everything to be fine also. He seems to think it's fuel pump related but I haven't had a chance to check it yet.


Posted By: Jllogan
Date Posted: June-27-2012 at 6:21pm
hmm possible I suppose. They are cheap throw on a new one I guess.

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http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001





Posted By: JoeinNY
Date Posted: June-27-2012 at 6:34pm
Your statement about the fuel pump on a marine engine being designed not to do that is incorrect. If the diaphram on the pump goes it will leak fuel into the clear transfer tube attached to the air cleaner and into the carb.

Your leak going to the carb is a serious safety hazard even if it stops when the engine isnt running. Try not to die! fix it asap.

The most likely cause is indeed dripping from the primary or secondaries which you should be able to see by looking down the throat of the carb while the motor is not running. Lately needle and seat valves have been proving faulty quite often. I have seen a bunch of them, new and used and I have had ones that look just fine to me- leak like a sun of a gun.

If you see one dripping... replace the corresponding needle and seat.

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http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001
1967 Mustang 302 "Decoy"
http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video


Posted By: Casey Buck
Date Posted: June-27-2012 at 7:30pm
I've fixed the leak going into the carb. I'm goin to check the fuel pump this afternoon and see what I find. Thanks to all who have replied to this post as it is very helpful info.


Posted By: kapla
Date Posted: June-27-2012 at 8:02pm
this thread belongs to the engine section.
This section is for new stuff or things that happen around the site.


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<a href="">1992 ski nautique



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