Carb Issue?????

[twn827]

I currently am running with a 1992 volvo penta 431b motor. i just replaced both exhaust manifolds and had the boat out last friday and it ran great. saturday when we put it in the water it fired right up and then stalled out in the lake. at first it sounded like the battery was the culprit but it did not jump or turn over. we took the carb cover off and it started right up. we ran the boat down the lake with no issues and then when we hit a no wake zone and lowered the throttle we stalled. again the boat would not start unless we took the carb cover off. when it started we ran back up the lake fine until we hit the no wake zone and went back on the throttle and the boat stalled again. to me this sounds liek a carb or fuel pump issue. but i do not understand why taking the cover off would make that much differcence. please offer your opinions

 

[insttech1]

Re: Carb Issue?????

If the carb cover is a flame arrester then the fins may be clogged, impeding airflow to the engine. I sprayed mine out (off engine, of course...) with a large amount of carb cleaner, holding it up so sunlight to ensure none of the fins were clogged....just a thought.

 

[twn827]

Re: Carb Issue?????

ok i had the carb rebuilt and the motor started up. did a compression test and #3 cylinder was showing no compression. upon investigating found a blown head gasket. getting the head milled and then putting back together. my question is could the carb running too lean cause this issue?