Chev 350 popping from carburator

[Celebrity240]

Hey, I swapped my Merc350 with a '79 Chevy 350 at the beginning of the season. Ran perfect until last weekend. As soon as I give it some throttle, I get loud popping from the carb and the boat goes no where. I cant even hit 5mph. I noticed that my gasket from the Intake Manifold is cooked since I have oil all around the manifold, and I see air bubbles coming from the sides of the manifold. Could that be the reason for this issue? For the past week, the popping would happen from time to time, I noticed that my top speed was getting worse and worse, and now its so bad that I cant even get the boat to tip.

Please help!
Thanks,
Dan

 

[cpubud]

Re: Chev 350 popping from carburator

replace the motor again using a marine engine.

 

[Celebrity240]

Re: Chev 350 popping from carburator

Please reply only if you have something SMART to say

 

[gadget73]

Re: Chev 350 popping from carburator

Massive vacuum leak causing an extreme lean condition. Fix the intake leaks and you should be good. If that doesn't completely resolve it, try changing the fuel filters as well.

 

[bigskiohio]

Re: Chev 350 popping from carburator

marine engine or not has nothing to do with it.plenty of auto engines out there running in boats.

 

[Celebrity240]

Re: Chev 350 popping from carburator

Thanks a lot guys, will try it tomorrow

 

[nitrosteve]

Re: Chev 350 popping from carburator

Is it popping consistently or just occasionally. The reason I ask is I blew a head gasket between cylinders once and it would pop out the carb every time either of those cylinders fired. It was a bear to trouble shoot since I had no water in the oil. I hope this isnt your issue I wouldn't wish that on anyone. lets just hope its a vacuum leak.

 

[Celebrity240]

Re: Chev 350 popping from carburator

Well it was occasionally and it got more and more often. Now, it pops all the time, when im reving it in neutral, its fine until I hit 5000rpm, unless i give it a lot of gas very suddenly, then it starts popping instantly. As soon as im in gear trying it in water, it happens right away after 1500rpm,i guess since it has more load then working in neutral.

Hopefully its not the head gasket, i don't see any water in the oil either.

 

[bruceb58]

Re: Chev 350 popping from carburator

Its a lean condition. Could be cause by many things:

1) Carb needs to be rebuilt
2) Vacuum leaks
3) Float level
4) Fuel delivery. Fuel pump or clogged fuel supply.