Divorced Choke or Manual Choke?

[Tcwivwallace]

Hey Everyone! Its been awhile since I posted on here, but since the last post, I have got quite a bit done. The truck is inspected and I have since put over 2000 miles on it with limited issues. With the cold weather beginning to bear down on us in the Northeast, it is time I address my next project, the choke. When I first bought the truck, it was summer and there was no need for the choke and that was fine, considering the PO had removed the choke plate, no idea why. Anyhow, We fabricated a new choke plate and we can't seem to figure out how the whole thing works. As the truck is warming, the choke is not opening as it should.If anyone can lend any advice on the topic, it would be incredible.

On a side note, I am also thinking about converting to a manual choke if that is simpler than repairing the divorced choke setup. I have the choke cable however I am not sure where to mount that cable on the choke mechanism. Like I said, any information is greatly appreciated!

Ted

[Tcwivwallace]

Here are some pictures of the Carburetor and the choke linkage.

[geezer#99]

For one thing that hose you have looped around needs to be pulled off up by the fuel inlet. Probably remove it all together and put a vacuum cap on the hose barb at the bottom end of the hose.
Then run a short hose from the vac pot to the barb near the fuel inlet. You need vacuum to pull in the arm on the pot so the choke can open fully as it warms up.

[dmjlambert]

Divorced Choke or Manual Choke? How about electric choke? I am liking mine pretty well, ordered a fresh carburetor from National Carburetor. They took a 1981 to 1986 model year Quadajet and put the 1969 throttle linkages on it.

[Tcwivwallace]

Thank you Geezer! I will give that a try tomorrow morning and see how that works out!

Do they make an electric choke conversion for the original carb? I might look into that if I have bad luck tomorrow.

[dmjlambert]

I ordered the 1969 Quadrajet online and then followed up with a phone call to ask them if they could "upgrade" it to electric choke. When I talked to National Carburetor on the phone, their guy explained to me that they could not add electric choke to a carburetor, but they could put together a later model Quadrajet that happens to have electric choke, and put the old-style linkage on it so it works with a 1969 truck. Then he looked up the price to see how much extra it would cost, and he found it was $20 less than the divorced choke carburetor I had ordered, so he sent me a $20 refund. I asked him if I should send the divorced choke and cover back to them as part of the core, and he said no, that is considered part of the intake manifold and is not included with the carburetor (if they were shipping me a 1969 Quadrajet).

There may be some sort of aftermarket electric choke add-on for a Quadrajet, but since a whole new Quadrajet is only about $220, I didn't consider it worth looking into, and I guess I just wanted a shiny new carb and wanted to be completely rid of any carb doubts. It wasn't really new, it was remanufactured, but it sure is pretty.

[geezer#99]

They make one that replaces the choke stove and link and mounts to the intake bolt.
http://quadrajetparts.com/electronic...evy-p-399.html

When you swap that hose draw a vacuum on the vac pot to make sure it's working. A little lung suction on the hose works.

[71CHEVYSHORTBED402]

Originally Posted by geezer#99

They make one that replaces the choke stove and link and mounts to the intake bolt.
http://quadrajetparts.com/electronic...evy-p-399.html

When you swap that hose draw a vacuum on the vac pot to make sure it's working. A little lung suction on the hose works.

To think my former mechanic talked me into a new Edlebrock for my driver, because I needed a choke. $600 or so installed. Perfectly good Rochester, but it's not like I lost it. I was in a hurry and have never pulled a carb before. I get to learn that on my 71. At a second glance, the mod is not for a 402. Doesn't mean they're not available..........Check, here it is: http://quadrajetparts.com/electronic...evy-p-400.html

[geezer#99]

FWIW I rigged up a manual choke once on my divorced choke quadrajet. Used a small bellcrank and bracket I built to replace the choke stove and link arm. Mounted it to the intake bolt. Worked similar to the electric choke one. Just easier to control. This was before electric chokes were available.

[Ironangel]

There is a divorced choke conversion available. http://www.carburetion.com/sitesearc...%20Conversions
To set a divorced choke properly you most likely will have to bend the choke rod as per the shop manual instructions. I have divorced chokes on both my 72 C/10's, they work quite well as long as the rod is bent to the correct length.

[Ironangel]

Heres a procedure for correctly setting the divorced choke.
1. Divorced Choke Systems (1967-1974)
v Disconnect the divorced choke rod from the lever on the passenger side of the carb. Leave it attached to the choke coil box on the manifold.
v Open the throttle slightly and fully close the choke.
v Push the choke rod all the way down into the choke coil until it hits the stop.
v At this position, the top of the choke rod should be level with the bottom edge of the choke rod hole in the lever on the carb.
v Bend the rod to obtain this relationship.
v Once complete, hook the rod back up to the lever.
v With the rod hooked up, push the choke rod back down to the seated position once again. This should fully close the choke blade. If the choke blade is not fully closed in this position, bend the choke intermediate rod that comes up through the body of the carb and attaches to the choke blade lever. Bend the rod so that the choke blade is fully closed.
v Remove the short piece of vacuum hose attaching the choke pulloff to the vacuum nipple on the carb. Attach a long (about 2’) vacuum hose to the pulloff.
v Crack the throttle slightly and push down on the divorced choke rod to close the choke fully. Release the throttle. Keep light finger pressure on the choke rod to maintain light closing pressure on the choke.
v Suck on the vacuum hose to retract the choke pulloff. If the pulloff does not retract, it must be replaced.
v With the pulloff fully retracted and light finger pressure on the choke rod, use your other hand to lightly push down on the forward lower edge of the choke blade to simulate the force of the air across the blade. This will open the choke slightly. At this point, measure the distance between the forward lower edge of the choke blade and the forward wall of the airhorn. This distance should be ¼”. You can use a ¼” drill bit as a simple gauge to check it. To adjust, bend the tang on the choke linkage where it contacts the choke pulloff rod.
v Re-attach the vacuum hose to the pulloff and the carb.

This completes choke adjustment for a divorced choke carb.

[Tcwivwallace]

I went out today and got some vacuum hose and vacuum caps for my carb, and unfortunately, I discovered the choke pull-off is bad. So, Wednesday the new pull-off will be in and I can finally get this choke working! Thank you guys for the information and help! Happy New Year!

[Tcwivwallace]

Update: I got the choke pull-off installed and it is properly pulling the choke blade about 1/8", however, as the truck is warming up, the Choke Blade is not moving. I took the choke thermostat spring off the truck and I heated it up with a hair dryer and it relaxes and opens up. However, when it is on the truck, it does not open up. Could this be a choke coil problem? How is the heat conducted into the coil from the intake? Thanks Everyone for replies!

[geezer#99]

Originally Posted by Tcwivwallace

Update: I got the choke pull-off installed and it is properly pulling the choke blade about 1/8", however, as the truck is warming up, the Choke Blade is not moving. I took the choke thermostat spring off the truck and I heated it up with a hair dryer and it relaxes and opens up. However, when it is on the truck, it does not open up. Could this be a choke coil problem? How is the heat conducted into the coil from the intake? Thanks Everyone for replies!

Plugged heat crossover. The coil is heated from the exhaust heat in the crossover under the intake plenum.
LIkely plugged with carbon deposits.

[Tcwivwallace]

So what is the fix to that issue?

[geezer#99]

Pull the intake and clean it out!!
Hard job!
Carbon packs in real tight. Like solid!!
You need to drill into it and chip it out.
And then once you get it all done and installed you find out the heat riser is kaput.
Or put on an electric choke in that link I gave you.
Or get a new intake that has the choke pad on it.

[Tcwivwallace]

Considering one of my intake bolts is broken.. I think I'm going to take your advice and go to an electric choke. Thanks!

[geezer#99]

When you do take pics and post a how-to thread!
Share the info.

[James the III]

Originally Posted by dmjlambert

Divorced Choke or Manual Choke? How about electric choke? I am liking mine pretty well, ordered a fresh carburetor from National Carburetor. They took a 1981 to 1986 model year Quadajet and put the 1969 throttle linkages on it.

Is that a ccc-q-jet?

[dmjlambert]

What is a ccc-q-jet?

[James the III]

Originally Posted by dmjlambert

What is a ccc-q-jet?

81-86 q-jets where CCC (computer controlled carb)

[dmjlambert]

Hmm, I don't know. The only electric connection is 12V to the choke. It looks like a plain old carburetor to me, except it does have more vacuum ports. Here is the thread where I talked about all those ports with you guys: http://67-72chevytrucks.com/vboard/s...d.php?t=711266

[dmjlambert]

You made me curious, so I looked at the carburetor and it has a sticker on it with National Carburetor's part number ND-4478. Then I went to National Carburetor's site and looked it up to find this line:
1981-86 Transmission=All Description=305"-350" Eng Non Computer MOST COMMON Type=M4ME
The all caps on words most common is the way they list it, not my emphasis. So, no computer for this one.

This is what it looks like installed:

[James the III]

Originally Posted by dmjlambert

You made me curious, so I looked at the carburetor and it has a sticker on it with National Carburetor's part number ND-4478. Then I went to National Carburetor's site and looked it up to find this line:
1981-86 Transmission=All Description=305"-350" Eng Non Computer MOST COMMON Type=M4ME
The all caps on words most common is the way they list it, not my emphasis. So, no computer for this one.

This is what it looks like installed:

I asked because the photo you have in post 42 the bright alum part on the top that looks like upside down funnel is where the idle speed selnoid would go.. on a ccc . and my older non computer j-jets don't have what your's seems to have in that spot.

[dmjlambert]

Originally Posted by James the III

I asked because the photo you have in post 42 the bright alum part on the top that looks like upside down funnel is where the idle speed selnoid would go.. on a ccc . and my older non computer j-jets don't have what your's seems to have in that spot.

That is interesting. I wonder if they made a dummy plug of some sort to go in there for non-computer trucks, so they could just use the same carburetor body.