Carb Adjustment

[elite222]

1987 260 hp Mercruiser I had to replace the heads and thought I would tune her up while I was at it. When adjusting the idle mixture screws on the carb I couldn't get the rpms to fluctuate at all, either all the way in or 4 turns out, while in gear, warm, at an idle. So I rebuilt the quadrajunk (yes I did boil it and used 130psi air line to blow it out), reinstalled and it still will not fluctuate the RPM's. Any ideas?

 

[Wart T]

Re: Carb Adjustment

Idle circuit is still messed up. You did remove the screws? Sorry, you didnt do a good enough job.

 

[Mahoney]

Re: Carb Adjustment

I am actually having the same isssue with my OMC 225 V8, cant get the rpms to change much with the idle screws only by manually manipulating the choke, which when full open is making the mixture to lean. As I close it about 30 % rpm's go up drastically. Engine is fully warm and at operating temp when I do this, so I am assuming the idle screws should have more of an effect. I too took carb apart and blew out all the channels with compressor, however I did not remember blowing out the idle mixture holes where the adjustment screws went in.