Yamaha 50 HP Idles to 3000

[Uncle Tod]

On a fairly inconsistent basis (15% of the time) when I put my boat in neutral after it has been running for a while, the idle will jump up to 3000 rpm. If I shut the motor off and restart it, she goes back to normal idle around 1000. I replaced the gas line and am 99% sure this is not the issue. Other than this, the engine is running fine. This issue only happens in neutral, not when the drive is engaged. Thanks for any advice to troubleshoot.

 

[racerone]

See if control box pulls the throttle arm to the idle stop ( with a bit of preload ) each time.

 

[boscoe99]

Is the motor a two stroke or a four stroke model? If four stroke is it carburetted or fuel injected?

 

[Uncle Tod]

See if control box pulls the throttle arm to the idle stop ( with a bit of preload ) each time.

i thought of this, but it will idle way down low in gear, and it will wait about ten seconds before revving up to 3000

 

[Uncle Tod]

Is the motor a two stroke or a four stroke model? If four stroke is it carburetted or fuel injected?

4 stroke and Carb. Maybe a tuck lever in the carb?

 

[Uncle Tod]

4 stroke and Carb. Maybe a tuck lever in the carb?

Maybe start with some carb cleaner spray?

 

[99yam40]

Maybe start with some carb cleaner spray?

you will need to look at the carb throttle plates to see if they are closed when this high idle happens.
if they are closed when they should be at idle, then I would monitor the timing with a timing light.
advanced timing could bring the idle up