OMC engine issue

[Alan1h]

I have a OMC 3.0L Cobra, 1989, Jasper rebuilt with 100hrs. this year.
Ran great... still does with this one issue.

Starts and idles at 600RPM but after running and bring it back to the dock...
I slow it down to go into neutral and it jumps to a fast idle at approx 1200RPM which doesnt make it much fun to try and dock!

I also Pertronix electronic ignition conversion.
New plugs and timing checked.

If I turn it off and start it back up, it idles at 600rpm again.

Any ideas???

Thanks,

 

[Don S]

Re: OMC engine issue

You probably need to adjust the throttle cable so it slightly preloads the carb linkage to the idle position.

 

[subcrx]

Re: OMC engine issue

did you try overriding the throttle linkage to the carb?

 

[Alan1h]

Re: OMC engine issue

Overiding the throttle linkage? I'm not sure what you mean...

 

[subcrx]

Re: OMC engine issue

Disconnect the throttle linkage from the carb. close it by hand and see if it goes down

 

[MBAKER]

Re: OMC engine issue

does it idle slow when cold, then as soon as everything comes up to temp the fast idle shows up?

If so could be the idle speed is just to fast, all engiens will idle a little faster as they warm up. So even though the idle speed is correct when cold, once it warms up its too fast. May just need to be readjusted after the boat is warmed up and running, and then when cold you may have to put on fast idle in neutral to warm it a little before heading out.