Can someone please explain how an electric choke on an edelbrock carb is suppose to work? I'm not an idiot but correct me if I'm wrong, I don't think something is set up right on my carb. Here my scenario.

It's cold in the morning. Pump the gas once or tap it to engage choke. Crank engine and she fires up. Idles high at about 1000-1100 rpm. As she runs and warms up the choke is heating as well and the idle INCREASES to around 1500 rpm after a while. I go tap the has and it kicks down to normal idle.

Now My understanding is that as the choke heats up it should be moving itself off the high or cold idle cam and idling down "automatically". Is something not set up right or am I just a carburetor greenhorn? I've had a few GM cara with stock carbs so I'm not particularly familiar with electric chokes but they always idled down.

Thanks!

 

You will have to kick it down like you are doing. The throttle spring on the throttle cable has too much pressure on it. All that pressure is pushing on one little screw that is sitting on the fast idle cam, and when the choke starts opening, the linkage doesn't have enough power to slide the fast idle screw down to the next step in the cam.

All carbs are pretty much this way. If it worrys you that it's revving too high, you can adjust that fast idle screw down some. Get it too low though, and it won't want to keep running after you first start it up.

 

Yep, that sounds normal to me too.

 

What is a good speed for the fast idle to be set at that? I suspect that you would want it to be as low as possible without stalling the engine, correct?

 

I think there are actually several steps on the fast idle cam. But, you are right in that the goal is really just to keep the engine running fast enough to keep it from stalling. IIRC, the spec's call for something like 1250 RPM for the top step, but I don't use a tach for that and just dial it in by ear. Especially on automatic-equipped vehicles as I don't like that serious clunk when you put them in gear.

 

So I don't understand this "mentality" haha. The purpose as the choke opens is to idle down but because of the return spring on the throttle it holds it captive and as more air enters it idles up? so in theory of the choke had more "oooomph" if would slide the cam down as it warmed.*

Is there any way or thoughts on how to fix this? I have my high idle set pretty low already but then it idles high as it warms. Would a lighter spring on the throttle help or maybe adjusting the choke closed a little more? Just curious.*

This is my work truck so lots of time I fire her up and run into the shop to gather tools for the day. I hate having to run out and kick the idle down. Just curious if there's anything I can do!*

I suppose if I want to get REAL technical I can find a way to install a solenoid of some sorts to a timer switch. When I start the truck, activate the timer switch and have it kick the idle down after two minutes? Haha or is this just a bit crazy?????*

 

The choke can't overcome the throttle spring regardless of how far on you adjust it. But, you can adjust the fast idle lower so that it is barely running when you first start up and then it will speed up as the engine warms up. That is just the way they were all designed.

 

Yes, needing to kick it down as the engine warms up is just how carbureted engines work.

 

I know my neighbors hate me taking the truck to work in the mornings now that its cold out due to my exhaust. Like everyone said there is no way around it unless setting high idle down but then you'd probably be sputtering yourself out depending on how cold it is there.

 

If you wait about 10 seconds before jumping out, you can usually kick it down a least one step before you get out. Tromp it really good and see how low you can kick it down.

I believe the best solution for you is to get a fuel injected truck. Sorry that sounds a little blunt, but this is one of the many reasons they got rid of carbs.

They have to set the idle high when the engine is cold. The fuel doesn't want to stay a vapor when it hits the cold intake, so keeping it moving fast helps that. And the oil is stiff so it takes some power to turn it till the oil gets warmed up.

 

Good call that's what I do and didn't even think to mention it. I start up then give a tap after about 5-10 then let her rise up but it doesn't get as high as it would if I just started it. It's about 1000 rpm doing it that way as compared to 1250 rpm by just tapping it starting it and letting it do its own thing.