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View Full Version : Electric choke on Holley 600DP won't idle down.



NB141FD
01-13-2013, 02:20 PM
I installed a Holley electric choke kit on my new Holley 600DP carburetor and am having idle problems. The choke works perfectly; it closes on start up, idles at 1600rpm and slowly opens the choke plate as you would expect. I have a good 12 volts to the choke and a good ground. In addition, I have teed into the distributor vacuum line per instructions. The problem is that the idle will not come down as the choke opens. It will idle at 1600rpm forever if I don't blip the throttle. I was under the impression that as the choke opened the fast idle cam in conjunction with the fast idle screw would reduce the rpms down to my normal idle speed (950rpm). I have checked that the red idle cam is above the choke arm as it should be and have checked to see that the fast idle screw and cam are not binding anywhere, they move freely. I have noticed that as the choke opens the red fast idle cam seems to hang up (stay stationary) as the choke arm drops and the choke opens. I can move the fast idle cam to drop the rpms but it seems that the choke should be doing this for me. What am I missing?

TIA, Tony

Danny Cabral
01-13-2013, 02:29 PM
The problem is that the idle will not come down as the choke opens. It will idle at 1600rpm forever if I don't blip the throttle.
I was under the impression that as the choke opened the fast idle cam in conjunction with the fast idle screw would reduce the rpms down to my normal idle speed (950rpm).
No, you have to physically tap the throttle to kick the fast idle cam screw off its current step. That's how an electric choke functions.

NB141FD
01-13-2013, 08:38 PM
Really? Thanks for the response Danny. Somehow I thought that the fast idle cam "stepped down" the idle as the choke plate opened up and the engine approached operating temperature. As you can probably tell this is my first experience with an electric choke. Thanks again, I appreciate the info.

Tony

Danny Cabral
01-14-2013, 04:21 AM
Somehow I thought that the fast idle cam "stepped down" the idle as the choke plate opened up and the engine approached operating temperature.
The fast idle cam/screw is held against the throttle return spring tension.
The choke plate moves automatically with the choke thermostat linkage.

lawler
08-23-2013, 02:34 PM
The Holley videos clearly state that the idle is stepped down to normal idle as the choke plate opens. The graduated cam is specifically design the hold the idle at various levels as the engine warms up. If you were intended to blip the throttle to lower the idle and disengage the cam, then why graduate it? See link below.
http://holleytv.com/?p=437

Danny Cabral
08-23-2013, 06:10 PM
The Holley videos clearly state that the idle is stepped down to normal idle as the choke plate opens.
Yes, if you're driving the vehicle (throttling), the idle speed will automatically step itself down.


The graduated cam is specifically design the hold the idle at various levels as the engine warms up.
Yes, but the choke thermostat opening is not designed to step the idle speed down, unless the throttle is depressed.


If you were intended to blip the throttle to lower the idle and disengage the cam, then why graduate it?
It gradually steps down because the cold engine won't tolerate a complete fast idle cam disengagement.