Re: Mercruiser I/O Dieseling
Welcome to iboats!
There are a number of reasons an engine will run-on after shut-down:
1. Idle speed set too high or failure of the the throttle to return to the idle stop (loose or sticking throttle cable).
2. Engine running too hot or hot spots in the combustion chambers due to localized carbon buildup.
3. Gas that is too low in octane (may occur if the gas is too old).
4. Improper ignition timing.
