25hp Mercury 2 stroke sometimes idles too fast.

david860

Cadet
Joined
Aug 1, 2013
Messages
12
I have a 1996 25hp Mercury 2 stroke outboard. The carburetor was professionally rebuilt one year ago and the choke solenoid was replaced. I have put 15 hours on it since the work was done. Sometimes the idle speed is too high and it won't come down. Other times the idle speed is fine. Although it is electric start and remote, I only start it with the pull start. I do not have a battery connected. Any ideas what could cause the high idle?
 

enginepower

Petty Officer 1st Class
Joined
Jul 5, 2014
Messages
260
How high are you talking? Have you made sure the throttle is returning to it's stop? An air leak can cause high idle and even engine damage if it's bad enough. Slack in timing advance setup could give it some extra rpms too if it has slack and staying on advanced side.
 

david860

Cadet
Joined
Aug 1, 2013
Messages
12
enginepower: It can idle up 1800 rpm, but it is not consistent; sometimes lower. I'm using the manual choke and I noticed that when I push it in, it is not pushing the throttle down hard. There is a small Phillips head screw adjustment that I turned in so that it pushes firmly against the throttle. I'll try that on the water to see if that helps. If not I'll have to check out the timing. Thanks for the input.
 
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