82 Mercruiser 228 5.7 GMC idle problem

[sailor26]

Just bought a 82 Cobalt with a Mercruiser 228 5.7 GMC 4 barrel carb. It's been at the shop (a mercury mechanic) for almost 3 weeks now. The engine won't idle, floods and stalls. He bypassed the gas tank because of water and debri. He rebuilt the carb and it was still doing it. I bought a rebuilt carb and had it installed, still idling rough, flooding and stalling. Last I knew he had not checked the fuel pump. Any other suggestions?
The boat hadn't been used for the last 2-3 seasons. The old carb and filter were really gunked with water and debri.

 

[achris]

Re: 82 Mercruiser 228 5.7 GMC idle problem

Welcome to iBoats....

A few things... The 228 is not a 350 (5.7), it's a 305 (5.0)...

Check the intake manifold.. I've seen a few with holes corroded in the exhaust crossover passage, under the carbie. It lets exhaust gas into the intake and they idle like crap (if you can get them to idle at all)... Also check the usual suspects, compression, ignition timing, spark plugs and leads, dissy cap and rotor, points and condenser (if you have)....

Chris......