RPM's going up when in idle

[cs28461]

1992 88 hp Johnson -

Bought it not too long ago. First time out was working fine. Put the motor in idle and the rpm's stared climbing. Put it back in gear and motor made a hard thump. This did not happen everytime I put it back in idle. Maybe about 40% of the time. Boat had some gas in it that might be old. Could that be the case?

 

[tashasdaddy]

Re: RPM's going up when in idle

the motor is going to idle faster in neutral, do to no load on it. bad gas could effect it, timing plate not returning all the way to idle, could cause it. play, slop in the linkage.

 

[cdoliver]

Re: RPM's going up when in idle

pay close attention to the stop screw on the throttle linkage. If it isn't all the way against the block you either need to adjust the throttle cable or check the timer plate possibly restricting it from moving freely