rough idle and a lot of smoke, leak at top carb idle screw

[Tom Glandon]

I have a 1994 merc 40 horse 4 cyl , starts easy and idles as long as i keep the fast idle on but when i turn the fast idle off the dam thing stalls, whats up with that.

 

[Elmer Fudge]

Re: rough idle and a lot of smoke, leak at top carb idle screw

It looks like you may have a sticking float needle, try cleaning out the carbs.<br />Did you have a compression test done?