low idle

[22classic]

I have, new to me, a 1997 merc 454 mag, 350 hp, in a 22 Donzi Classic. The start up, cold, idle is way to low 400 rpm. I can not find the fast idle screw to adjust. In fact there does not appear to be the fast idle cam or screw anywhere. Not sure what the Carb brand is as I can't find a label. It might be a Carter, but that is just a guess. Does any one know of a carburetor that would be mounted on that engine that has no adjustment for idle while cold.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Bein' a '97, it oughta have the Merc/ Weber/ Carter AFB carb,....

The idle adjustment screw is on the portside of the carb, right 'bout where the cable attaches,....

 

[Bt Doctur]

http://www.boatfix.com/merc/Servmanl/16/16B5R2.PDF

 

[22classic]

Thanks you two. That's it, a Weber. I sure enough does not have a fast idle cam or screw. At least now I have what I need to tune .

 

[Rick Stephens]

Marine carbs do not have a fast idle cam. You are supposed to disengage the shift and use the manual throttle to speed up cold start. Because of the way boat gears work, you would not want a carburetor with a high idle, if you ever shifted into gear it would scatter parts.

 

[22classic]

Well, that makes all the sense. One would have to wait for warm up to safely shift. The 20 year old Donzi is my first gas inboard. Outboards and small diesels before. Thanks you three, I'm in a learning phase and appreciate your knowledge.

 

[Bondo]

I sure enough does not have a fast idle cam or screw.

Ayuh,.... Click on BD's link, 'n scroll down to page 5B-11, the idle speed screw is shown, 'n identified,.....
port-side of the page,...