Early 1990 Mercury 3 cyl 90 hp outboard Won't run on idle, high rev to start

bigvalley

Recruit
Joined
Aug 3, 2011
Messages
1
I purchased boat & motor roadside with reassurance it ran well. Motor starts sluggishly and won't run on idle. I typically need to prime carb with manual throttle release button and keep up on hi idle to keep running. Electric choke doesn't seem to work or make a difference. Compression test was 100psi, 100psi, 105psi. Any suggestions?
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Early 1990 Mercury 3 cyl 90 hp outboard Won't run on idle, high rev to start

If it seems fine wide open but just has idle problems it is time to clelan the carb. the same idle fuel passages accumulate crud and affect the idle quicker than the large main passage.
 
Top