Francesco
Veteran Member
I do not have the correct return spring. Im gonna have to order it. My kickdown cable looks like it is also too short and its keeping the throttle open even when i have the foot on the break.
Rochester Q-jet carb vs Holley 770 cfm
- Thread starter Francesco
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Francesco
Veteran Member
Thanks Brent! Im gonna read the book again. I might have a bad choke pull off. Im gonna check everything.
Francesco
Veteran Member
From what im reading, the choke plate has to be almost closed when i do a cold start.
Yes. The spring will be tight when cold. Moving the throttle when cold (with key off) lets spring tension pull the choke linkage to pull the choke closed and set the throttle linkage on high idle. This restricts air and pulls extra fuel thru the idle circuit. As soon as the engine starts, the choke pull-off opens the blade very slightly so the engine will run smoothly. As the electric choke spring is heated, it will loosen up and open the choke, but the throttle will stay on high idle until you move the throttle again, allowing it to go to regular curb idle.
Francesco
Veteran Member
Im going to tackle this on my own first. Thing is I dont know where to start. I read that the choke plate has to be open as much as a dime when its started. The thermostat has to be adjusted accordingly before the engine starts. Thing is, theres more then one adjustment. Does the fast idle cam need to be all the way down when I start the car? or all the way up? Do I have to adjust the mixture screws when the car is on fast idle? Do I have to adjust the fast idle when the car is at operating temp? What is fast idle adjustment? Do I adjust the curb idle when the car is in drive and warm? Do I determine rpm based on the cars manual? A mild modified cam will change that so then what would be the correct rpm for cold start and drive? Im going to test light the thermostat because i think the wire is faulty. The spring in the thermostat never seems to work. My high idle stays high when in park.
You are way over thinking it. The choke is only used to help richen the starting mixture and is linked to the cam that increases the idle when cold. It also keeps the secondary’s closed when cold. When the choke opens the hot idle cam should not be engaged. A lot of these adjustments are through bending rods. Good news is most of this stuff is usually close to where it should be. The choke should be slightly open when cold but the important part is that it is fully open when hot. Choke adjustment information is usually in the rebuild kit. All other adjustments are done when car is warmed up.
Yes. The choke pull-off will take care of opening the choke blade slightly when the engine starts. Otherwise, it will be completely closed when cold.
Have a really close look at the linkage, you will see how the fast idle cam comes I to play on a cold start. You can manually simulate how it works with the engine off and just playing with the linkage.
You have to figure out the spring issue though. The cold start system needs spring tension to work, and normal warm operation needs the spring totally unwound the other way in order to keep the choke off.
Have a really close look at the linkage, you will see how the fast idle cam comes I to play on a cold start. You can manually simulate how it works with the engine off and just playing with the linkage.
You have to figure out the spring issue though. The cold start system needs spring tension to work, and normal warm operation needs the spring totally unwound the other way in order to keep the choke off.
Francesco
Veteran Member
I just bought a test light and there is no power going to the thermostat...The wire to the spade connector is missing some copper strands. I guess thats why the spring is not heating up...Im soooo blind.
