[Mac88]

I know the purpose of a choke, and I've read a few posts and have a general idea how it works, but I'm still not quiet getting how to set it up. I have a Holley Street Avenger Carb (670), and I had to install a choke because when I bought the car, I guess the previous owner had removed it. Anyway, I have the choke installed. The notch on the black cap is centered on the index lines on the choke housing and the choke flap is completely closed. So, guess my first question is, at what point the flap should open completely. When I take my hand and manually engage the throttle, even with full throttle, the flap only opens about 1/4 of the way. I know I have to adjust the fast idle screw to about 1600, which I haven't been able to get my wrench on that screw yet. It's a pain. I guess my biggest concern is when should the flap open and how far should it open. I'm reading the Holley instructions, but I'm still a bit confused.

[S10 Racer]

Originally Posted by Mac88

I know the purpose of a choke, and I've read a few posts and have a general idea how it works, but I'm still not quiet getting how to set it up. I have a Holley Street Avenger Carb (670), and I had to install a choke because when I bought the car, I guess the previous owner had removed it. Anyway, I have the choke installed. The notch on the black cap is centered on the index lines on the choke housing and the choke flap is completely closed. So, guess my first question is, at what point the flap should open completely. When I take my hand and manually engage the throttle, even with full throttle, the flap only opens about 1/4 of the way. I know I have to adjust the fast idle screw to about 1600, which I haven't been able to get my wrench on that screw yet. It's a pain. I guess my biggest concern is when should the flap open and how far should it open. I'm reading the Holley instructions, but I'm still a bit confused.

The way I have always set them is to do it cold, before starting the engine. Remove the air cleaner, loosen the screws and turn the "black cap" so the choke will close fairly firmly. Turn the black cap in the opposite direction until you just start to see the choke opening and tighten the screws. Start the engine and let it warm up. Verify that the choke is completely open when the engine is at operating temperature. If not, make a small adjustment to open it up. This is the way I have always done it and have had no problems.

[Mac88]

Ok, another choke question. I have the choke installed, wired up, and running. My initial problem was starting the car. The choke gets the car started now with no problem. The question I have now basically as a follow-up is, I was told that within 2-3 minutes the choke plate would open completely up. It never did. The car was still running fine, but the plate only opened up about 1/4 of the way, or maybe a little more. So eventhough the car is running, from everything I've read, the plate should come completely open at some time. Any suggestions what I need to do next? There is a little smoke, but there was a little smoke before I installed the choke, so I'm not sure if that has anything to do with the choke.

[lg1969chevelle]

If the choke is still open 1/4 after 2 minutes, you should check and see you have 12V going into the connector. It's how much tight the flap is closed, because there is a piston inside the housing that forces the flap to open no matter how tight the flap is closes. The tighter the choke flap is, the longer it takes to open fully. In the Winter the flap will be more tighter making the motor to run at a higher RPM during warm up and less time for the flap to open during the summer months. The piston in the housing uses manifold vacuum to open the choke. If you use a big cam that produces very low vacuum, the choke will not open. The more overlap in a cam the less vacuum it produces. The result is a flooded engine.