Hi RPM'

[snowcone]

Mercury 40 HP 4-stroke starts and idles fine. Runs great at half throttle and full throttle. The problem is after running at full throttle. When I return the throttle to any position, even neutral, the motor will not idle down and I have to turn off the ignition to keep the engine from "over revving". After sitting for several minutes(more than 5}, engine will start and run fine again untill I go WOT. Does anyone know what causes this?

 

[latin monkey]

Re: Hi RPM'

have you checked your throttle cable for binding/sticking?

 

[Blevins]

Re: Hi RPM'

What year. And is it efi or carb. Are you using additives in your fuel?

 

[snowcone]

Re: Hi RPM'

Thanks Latin, will check this PM. Will let you know.

 

[snowcone]

Re: Hi RPM'

To Latin and others that had suggested solutions. When I removed the cowling I found a lot of dirt and a small "dirt-dabber" nest near the throttle lever. The linkage was performing OK but the throttle itself would not return to idle position. After cleaning the pivot point and applying silicon spray it worked as it should. Test run did work and I think its fixed. Thanks for the advice.