1998 Mercury 40hp 3 cyl high idle

carjockey

Recruit
Joined
Jun 1, 2012
Messages
4
I just purchased a pontoon with the above engine. The motor would not run very well under a load. It was a jet plugged on the bottom carb. After rebuilding and cleaning all 3 the motor runs great but will not idle slow. I have adjusted the idle position to its lowest setting as well as the linkage and the stator timing. On muffs it is currently idling at 1700 rpm. Any ideas on what I've missed or miss adjusted?
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: 1998 Mercury 40hp 3 cyl high idle

Adjusting the motor carbs,timming, and linkage should be done in a test tank or in the water as there is no back pressure on the exhaust while on muffs. Ruff adjustment on muffs is just to get the motor to run and will always idle high. Setting adjustments while in the water will make sure that the carbs are not set lean, and checking the timming, which causes burnt pistons and junk motors.
Oldman570
 
Top