Weird throttle problem..1985 40hp throttles by itself?

Joined
Oct 2, 2006
Messages
17
I've got an 1985 Evinrude 40hp that's acting very weird....it starts up fine and idles great. If I give it half throttle, it accelerates up a little...delays for a couple seconds...and then increases RPM's by itself almost up to what they would be a full throttle. When I back it off, the RPM's drop to where they should be, but then the engine slowly decreases RPM's by itself until the engine cuts out completely.

Does this sound like a jet problem in the carbs, or what else could this possibly be? It's almost like it can't decide if it's getting too much fuel or too little.

Thanks for any help!
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Weird throttle problem..1985 40hp throttles by itself?

it very well could be loose linkage, or bad cables, or link and sinc. get someone to move your controller and see if the linkage is moving properly. i had a lock nut come loose on my engine's linkage, and it would do what ever it wanted to. it could also be a carb problem, fuel delivery, but rule out the easy stuff first. post back your findings. welcome to the forum.
 
Joined
Oct 2, 2006
Messages
17
Re: Weird throttle problem..1985 40hp throttles by itself?

ok thanks I'll take a closer look at the linkages when i get a chance.

Also, is it possible that maybe the jets are so screwed up that it takes a while for the right amount of fuel to get through, explaining why it seems to accelerate to a higher RPM than what is indicated by the throttle placement?
 
D

DJ

Guest
Re: Weird throttle problem..1985 40hp throttles by itself?

The advance mechanism under the flywheel is reacting slowly.

It should move smoothly with throttle advance and decrease. You can verify this by advancing the throttle (in gear-ENGINE OFF) and then backing off. You will see the advance arm move.

If it moves slowly (delayed) gently lubricate the pivot points with some light oil. (3 in 1).
 
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