Choke is staying on too long?

[Momboy007]

Hello All,
I have what I hope to be a quick question.
My choke on my completely stock 396 works just fine, it simple stays on too long. It is an original 4M Carb (if that helps at all)
The fast idle appears good and when it is fully warmed up, it runs very well, it just seems when first fired up in the morning the choke stays on way too long and the truck runs terrible, or until fully warmed up, lots of smoke (black) in the mean time and running way, way too rich. I tried reading the manual on how to adjust the choke, but in all honesty, I did not "GET IT".
It is a California truck and, like I said completely stock, even has the smog pump connected.
P.S. the truck now has 36K miles on it now.
Thanks in advance for any help
Rick

[WorkinLonghorn]

I'm in Southern Calif. too and the first thing I do with any carb'd truck or car is disable the choke. You don't need one. I leave the "fast idle" hooked up for easier warm-up but to start you just need to pump it a few times crank it and work the peddle a bit until it runs on it's own.

[JimKshortstep4x4]

Check the choke pull, (the round part with a vacuum hose going to it).

If it is not working then the choke will do what you are experiencing.

If the choke pull is good then it will need some adjustment which is done by bending the choke pull link to make it shorter. The chokes can be made to work if you take the time to do the adjustments.

I have the stock chock on my 71 K-10 which I use for plowing in the winter and the choke has to work, especially on the mornings when it is below zero.

Jim

[john]

I would make sure nothing is dirty and sticking. WD-40 or something similar to lube all moving parts. If that doesn't help you might want to try a new thermostatic spring. They will get weak over the years. Also what Jim said about the choke pulloff sounds like that is more liklier to be the prob.

[Momboy007]

Thanks all,
Here is what I have done so far.
1. Cleaned and lubed all the associated parts with the choke linkage.
2. The choke pull down is working properly, I used a small vacuum source and verified, it does indeed pull all the way in.

I think the problem may be in the thermastatic coil, it seems that to function correctly, it would have to be Longer somehow, what I am trying to say is if I try to fully open the choke, the coil and linkage would need to be longer, but all the adjustments I keep reading about say to bend the linkage, which in my mind would make it shorter!!????
Do these coil units go bad? How would you replace one?
Thanks all again,
Rick

[JimKshortstep4x4]

Did you try adjusting the choke pull? If it does not open the choke plate far enough after the engine starts then you will have the loading up problem.

The coil should be good. Work with the choke pull on this problem since the coil closes the choke plate but it does not set the plate gap after the engine starts. The manual instructions say to use a gap setting tool for the gap but I have never seen the tool. My suggestion would be to bend the link a little at a time on the choke pull which shortens the link and increases the gap.

To lessen the tension on the coil you will need to go longer on the rod but I don't believe that this is your problem.

Jim

[JimKshortstep4x4]

To adjust how far the choke plate opening is with the choke pull opening it, bending the linkage is necessary. In the picture that I have posted the linkage to bend on this carburetor is the black one in the middle of the pic (your carb can possibly be different). To open the plate gap, bend the black part toward the rear. Small adjustments can make big changes so bend the linkage a little bit at a time and check the gap.

Jim

[Momboy007]

I think that should help lots, is the unloader adjustable? the little vacuum pully thing?
Thanks all again,
Rick

[JimKshortstep4x4]

The vacuum pull is not adjustable.

Jim