Pontoon Boat & Deck Boat Forum

i have a used 90 h.p mercury 4 stroke efi that i bought recently. i checked the oil level and it was way above the cross hatched area of the dipstick. it also was thin in viscosity and it smelled like gas was in it. my question is how would gas get into the oil system and what kind of repairs am i looking at?

Hard to say but you must change that oil and filter NOW. Then keep a close check on it before each start and if you are getting gas in oil again take it to your dealer. Gas in the oil will damage the engine very quickly.

Gas in oil in a carbed motor = bad float. Gas in oil in an injected motor = bad injector. Don't run it until this is fixed or you'll be buying a new powerhead after it seizes or throws a rod. Be glad you found it before either happened and take it to a competent tech ASAP.

Yes, as BMR said. Bad injector, should be inexpensive to fix but don't run motor until fixed.