Correct Fast Idle Speed at Ops Check

[James W.]

What is the ball park range for the fast idle speed during the flight judging Ops check... 1,500???

Also how do you adjust the fast idle setting on a Carter AFB?


Thanks,

James West

[Michael G.]

Re: Correct Fast Idle Speed at Ops Check

What is the ball park range for the fast idle speed during the flight judging Ops check... 1,500???

Also how do you adjust the fast idle setting on a Carter AFB?


Thanks,

James West

1500 rpm will have you in the ball park. Your service manual will cover fast idle setting on your Carter.

[Stuart F.]

Re: Correct Fast Idle Speed at Ops Check

Driver's side of carb; look for fast idle cam linkage (link arm from choke shaft end) and screw that contacts idle cam. Check speed (RPM) when screw is on highest notch on cam. If close, and you want to tweek it up or down, it is best to shut engine down as it is difficult to get tool on screw with engine running on high notch. Make adjustment, then restart engine making certain screw is back on high notch. It is not necessary for choke baffle plate to be completely closed, in fact it won't run too long that way. Let it relax to the unloaded position, assuming that it is properly adjusted as well. It is best to consult an instruction sheet or manual to do a complete linkage adjustment check if in doubt. These linkages don't easily get out of adjustment unless some commando has messed with it.

Stu Fox

[Clem Z.]

Re: Correct Fast Idle Speed at Ops Check

some of the fast idle specs in the GM shop manuals are for a warmed up engine so make sure you read the fine print when you set your fast idle cam.

[Duke W.]

Re: Correct Fast Idle Speed at Ops Check

Most AFB equipped OE engines have a fast idle spec of 1750, hot. In other words you set the fast idle with the engine fully warmed up, and 1750 hot will result in about 1500 cold.

Whenever asking a technical question about an engine one should list the model year and engine option, and the appropriate service manuals will have all the carburetor adjustment specs and a detailed description of how to check and adjust everything.

Duke

[Clem Z.]

Re: Correct Fast Idle Speed at Ops Check

Most AFB equipped OE engines have a fast idle spec of 1750, hot. In other words you set the fast idle with the engine fully warmed up, and 1750 hot will result in about 1500 cold.

Whenever asking a technical question about an engine one should list the model year and engine option, and the appropriate service manuals will have all the carburetor adjustment specs and a detailed description of how to check and adjust everything.

Duke

i would think the viscosity of the engine oil and the ambient temp would effect the cold idle speed do do your homework before the PV test

[John H.]

Re: Correct Fast Idle Speed at Ops Check

The fast idle specs in the GM Shop/Service manuals are a calibration number, based on having a fully warmed-up/normalized engine and setting the throttle tang on the highest step of the fast idle cam; neither of those conditions will ever occur during Operations judging or a P.V.

[Michael H.]

Re: Correct Fast Idle Speed at Ops Check

Here's the original discussion on the "fast idle speed" discussion. I think it was decided by most judges after that time that there was no such thing as a spec on cold engine fast idle speed.

https://www.forums.ncrs.org/showthre...speed&uid=3162