Mercury 3.5hp 4 stroke oil leak into carb

[QBhoy]

Hi.
after sorting many issues on a non running one of these, after lots of issues found, oil in carb from sump was certainly the main issue. I presumed from it being stored on its wrong side way up. Won’t bore you with all the things that were wrong with it. But long story short. Got it running perfectly. Then sat it down on its side the correct way up as it should be. Went back to it a day later and it still managed to leak oil up and out through carb. Oil level seems correct on sight glass.
Usually don’t look on the internet for solutions to such things. But I did. Seems to be lots of issues with these wee things.
Im not usually a 4 stroke fan on engines this size. But it took my fancy for some reason. I can definitely say that the carb looks like cheap crap compared to my numerous other small and older 2 stroke Yamaha’s.
Any of the pros found or are aware of this being a particular issue with these engines ? It’s around 10 years old.

 

[winkbyc1993]

unsure if you have found an answer to this one. but I am having the exact same issue. I believe it to be a piston ring issue. I've disassembled the powerhead to get at the piston. they look ok but there is lots of burnt oil on the piston head and the combustion chamber. I'm going to give it a complete gasket job and new rings. side note, I also had some oil on the floor where I placed it last fall coming from the lower unit. definitely motor oil and not gear lube. if my thoughts are correct the oil is escaping past the piston, out the exhaust manifold and down the exhaust through the lower unit... I guess ill drop 100 bucks and see what happens... she runs ok but boggs down every now and then with a big poof of blue smoke. deff burning oil...