Fast Idle Cam Adjustment - Again

[John L.]

Just wanted to make sure I understand the proper procedure to adjust the Fast Idle Cam after reviewing numerous Threads on the topic in the Archives.

1) Bring engine up to operating temperature, 2) Manually place lever on the high step of the cam, 3) Adjust idle speed to about 2,000 RPM, 4) Turn off engine and done.
Is this correct?

Then, next time I drive the car from a cold start, just hit gas pedal once to set the choke then with my foot off gas pedal, crank engine and at point when she is about to turn over hit gas pedal again, right?


Thanks

[Timothy B.]

Re: Fast Idle Cam Adjustment - Again

John,

You have it right, just remember when you set the 2000rpm fast idle, it's set using the adjustment on the passenger side of the Holley not the idle speed screw, I know that's what you mean. The choke coil adjustment is separate from this and is very important to check because the choke blade needs to be full shut for the slow cranking engine to pull fuel from the booster venturi on a cold start.

[Duke W.]

Re: Fast Idle Cam Adjustment - Again

That sounds about right, but review the fast idle adjustment procedure in the CSM. You need to first make sure that the choke valve fully closes when the engine is cold. On an AFB you then bend the fast idle cam link as required to line up the index mark on the cam with the fast idle screw axis. Holleys should be similar.

On a cold start let the fast idle stabilze before touching the throttle - a few seconds at least, and the speed will be about 2-300 RPM less than the hot setting speed you used, which is specified in the CSM. Then you can kick the throttle if you want, but sometimes it's easier to not touch the throttle and drive off depending on what you have to do to get out of the garage. On a typical downsloping driveway you can usually ease off the clutch pedal enough to get the car to move onto the slope, then let it coast down the driveway, turn onto the street, and drive off.

The choke coil will gradually release the fast idle cam as it warms up.

Duke

[John L.]

Re: Fast Idle Cam Adjustment - Again

Tim, I must confess I was going to adjust the idle speed screw, what adjustment is on the passenger side of the Holley, does it have to do with the position on the cam high step where I place the lever?

[Timothy B.]

Re: Fast Idle Cam Adjustment - Again

John, Yes, it's the lever that rides against the plastic fast idle cam on ORIGINAL Holleys. There should be a screwdriver slot in the lever so gently bend it to increase the fast idle speed when it's put on the highest step after full engine warm up.

Get a book and go through all the choke adjustments, the Holley choke adjustment is pretty simple. Keep in mind on the aftermarket Holley there may very well be a screw on the passenger side to turn, I know the 2818 (1965 Holley) has one but your choke should be like the one on my 67 300hp car.

[John H.]

Re: Fast Idle Cam Adjustment - Again

Tim, I must confess I was going to adjust the idle speed screw, what adjustment is on the passenger side of the Holley, does it have to do with the position on the cam high step where I place the lever?

John -

See the link below to an article I wrote on late Holley choke and fast idle operation and adjustment.

http://www.lbfun.com/warehouse/tech_..._Idle_Tech.pdf

[Jerome P.]

Re: Fast Idle Cam Adjustment - Again

John,


Well written article.

[John L.]

Re: Fast Idle Cam Adjustment - Again

Thanks John, the information you provided has been most helpful and first time I have seen the procedure in print.

[John H.]

Re: Fast Idle Cam Adjustment - Again

Thanks John, the information you provided has been most helpful and first time I have seen the procedure in print.

John -

That was published in my "Tech Bench" column in "Corvette Enthusiast" magazine in 2004.