having carb leak down issues i think.

michaelkeb

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when my boat is cold i fill the bowl on the carb and touch the key and it fires right up. then i run for an hour and stop and fish for 5-6 hours and its like my motor is locked up. it dosent want to turn over then after a couple minutes of trying it will fire off. is my carb leaking fuel into the intake and thats whats causing it? Any ideas
 

PatinIdaho

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What do you mean,( it's like motor is locked up ) Is it bumping back as your tying to spin it? Or not spinning at all? Also what motor and carb combo ya got?
 

michaelkeb

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yes its like its locked up. I have the aq225d and a rochester quadrajet 4 barrel. i was thuinking maybe the fuel is leaking into the intake and filling a cylinder and thats whats causing it.????
 

michaelkeb

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you turn the key and iits just clunk clunk everytime ou turn it. then it finally starts to turn over and finally starts
 

PatinIdaho

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Would not think a carb could leak that much and with a warm engine some would evaporate. I have seen a weak starter do what you describe I would probably look at water getting into a cylinder from a bad/leaking exhaust manifold first. Pretty easy to do. If there ok then you ruled out one big problem and can move onto having the starter checked out. Kind of a pain but if good you can rule it out.
I just don't think a carb can do that the way you describe it. That would take a lot of gas.
I just replaced my Qjet we have the same engine. It was so bad that after i got it started and ran it for say 1/2 hour then stopped to fish for a little while it would leak all the fuel out from the two welch plugs on the bottom and flood the engine but at no time would it ever not spin over. New carb now purrs like a kitten!
So anyway from experience im betting its water getting into a cylinder.
I had this happen on a ole Merc888. Small leak in exhaust manifold would allow a little water into a cylinder causing it to hydro lock and do as you describe. After a few minutes the water would be forced passed the rings and it would spin and start. Took me a few to figure it out as i never seen water in the oil.
Turns out a small amount of water will evaporate out of hot oil and you will never see any signs of it.
Now im no expert and just telling you my experience so take it for what its worth!
 

dennis461

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yes, a quadrajet carb can do that, You risk bending a connecting rod everytime it happens. Goggle leaking quadrajet and find the repair method.

did I mention you could set your boat on fire?
 

PatinIdaho

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Hmm did not know a Qjet held that much fuel in the bowl to leak out and cause this problem. Guess ya learn something everyday!
Mine was leaking out of the usual place. The 2 little plugs on the bottom. Easy enough to epoxy over but i figured the thing was over 30 years old so i replaced mine.
 

michaelkeb

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how do you check the exhaust manifolds to see if they are leaking water into the cylinders? wouldnt that foul the plugs with water?
 

PatinIdaho

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Mine never did. Mine was a gasket leaking at the manifold riser joint. Was easy to see after i took it apart. Have you checked your plugs for rust or a plug that is cleaner then the rest?
Might be carb though as dennis461 said.
Sure do wanna know what ya find when you fix it!!
 

michaelkeb

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No but I'm going to check the plugs and I guess remove the manifolds and elbows to check them. What am I looking for when I remove them?
 

PatinIdaho

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A clean dry joint.
Or inner cracks, Rust streaks inside, Eroded where the two parts mate together.
 

captmello

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both have water running through them, you just need to pull the elbow, four bolts on top. Loosen the big hose clamps, take some pics.
 

dennis461

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how do you check the exhaust manifolds to see if they are leaking water into the cylinders? wouldnt that foul the plugs with water?

This one's easy/
By now you know the conditions leading to your engine lockup.
So, next time before turning the key, pulls the sparkplugs.
Crank over the engine and see what squirts out, gas or water....

Wear safety glasses and NO OPEN FLAMES
 

michaelkeb

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Jun 2, 2015
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Ok guys thanks I'll check it out and let us know. It won't be till Wednesday of next week till I do it. But I'll keep us posted
 

michaelkeb

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Jun 2, 2015
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ok pulled the manifolds and found one to be bad. so im guessing the carb is not the issue. gonna replace both manifolds and elbows. also replace the carb but at a later date. thanks for all the help guys.
 
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