1994 Mercury 75 idles rough

[kennycat1956]

My 75HP Mercury idles rough and seems to smoke more than it should when idling. The engine seems to smooth out when it tops the water and appears to run good. <br /><br />I realize it is better to smoke than not. It has the oil tank on the engine. Straight fuel only in fuel tank. Also, should I remove the oil tank and pre-mix the fuel? <br /><br />My 7 yr old really likes this boat.

 

[Exjake]

Re: 1994 Mercury 75 idles rough

I have a 1991 75 HP, it also smokes a lot at idle, at higher rpm it cleans up and runs great. I have tried different brands of oil and checked the adjustment on the oil pump, its still the same.