Rpms up and down at idle

[mudd_mickey]

I started it up last night and ran it for about 5 minutes at idle and the idle rpms would fluctuate from around 900 to almost 2100 just sitting there. The motor wasn't in a bucket, just running water through her with ears.

This didn't happen when I had her out a few weeks ago.

What causes the idle to fluctuate like that? I've found a lot of post talking about similar issues but they all talk about WOT rpms. Fuel lines?

1993 Johnson Oceanrunner V4 140
Model# VJ140TXETF

Thanks in advance

Mudd

 

[tashasdaddy]

Re: Rpms up and down at idle

dirty carbs, linkage, throttle plate (butterfly) not closed, flooding.

 

[JUSTINTIME]

Re: Rpms up and down at idle

i would say carbs or fueling issue

 

[Kevin70]

Re: Rpms up and down at idle

Maybe a ruptured carb float??? or a sticking float.