Q jet idle problem

[chris0061]

Mercruiser 260 runs great except for Idle, I've tried adjusting the idle screw and I get it to idle about 1000 rpm then it will fall off and die. Ive adjusted that screw countless times and every time I get it to even come close to Idling it will all of a sudden fall off and die. The carb was rebuilt over a year ago when I had it on another engine, I put it on a fresh rebuild and last year it had some trouble idling at times. I put that same engine in another boat this weekend and fired it up for the first time since last fall when I winterized and now I'm really having a tough time getting it to idle.

 

[achris]

Re: Q jet idle problem

Sounds like a blockage in the idle circuit somewhere... I'd pull it off again and completely strip it and start again... Soak it in cleaner, blow out all the passages with clean DRY air, check all the adjustments and go from there.

Chris......

 

[JustJason]

Re: Q jet idle problem

Check to make sure you don't have a vacuum leak also. Spray some foaming oil around the intake perimeter, the carb base gasket, and the outside of the throttle shafts on the carb itself.
1000rpms is way to high. If everything else is correct, that motor will idle smoothly at 500 rpms (no load).

 

[zbnutcase]

Re: Q jet idle problem

And make sure the ignition timing is correct. 'nutcase