My MerCruiser MCM 43 litre

Engine "dieseling" &#4

Engine "dieseling" (runs backwards) when I turn off the ignition switch. See my other post 06-28-09 0549 pm about hot starboard exhaust manifold and a cool port manifold. Would this have anything to do with the "dieseling? Thanks Don

Heavy carbon buildup in combus

Heavy carbon buildup in combustion chambers and valves w/excess fuel from carb. Shut it off in gear and decarbonize engine. Check that carb throttle is closing when pulled back and turned off.

Thanks again Guy. What's

Thanks again Guy. What's the best way to de-carbonize the engine? Don

"Get a can of SeaFoam. Bring

"Get a can of SeaFoam. Bring the engine up to operating temp. Have a fire extinguisher at hand. Remove the flame arrestor and bring the RPMs up to 2,000 and maintain that level as you SLOWLY pour half of the can of SeaFoam into the carb. while keeping the engine running and then shut the engine off. Pour the balance of the SeaFoam into the fuel tank. Wait 15-30 minutes, install the flame arrestor and restart the engine and keep it running for 15 minutes. Even better would be to take the boat out on the water and run it at 3500-4000 RPMs for 15 mins. Repeat if necessary."