Holley 1908 carb setting

[Pete W]

Tell me if this is right....

My Holley 1908 idle speed screw is turned all of the way in and the mixture screw is about three turns out to give me an RPM of about 700 with the choke open all of the way.

Will this fly? Seems like I shouldn't have the idle speed screw turned all of the way in. Forget the mixture screw 1 1/2 turns back from seated to start like the manual says. The car will never run at that setting. I can't find a vacuum leak.

Thanks,

Pete

1961 Comet, 144, 2.77 manual, 1908 with auto choke

 

[SandiaMan]

I always started with one and half turns out from seated on both valves to start with. Then fine tune from there

 

[JimKoz]

I'm not familiar with the 1908, so the direction of the idle speed screw doesn't mean much to me.

If you have to CLOSE the throttle and richen the mixture to get the right idle, then you've probably got a vacuum leak.

If you have to OPEN the throttle and richen the mixture to get a decent idle, then your ignition timing may be retarded.

Be sure to check the vacuum advance unit on the distributor too. If it's bad, you'll have both a vacuum leak and late timing.

Don't put too much faith in the timing marks if your engine is timed from the outer ring of the harmonic balancer. The outer ring is rubber-mounted and can slip by a few degrees over 40+ years. That causes the actual advance to be a few degrees less than the timing light reports.

Jim Kozisek