OT. GMC choke

Phlash-OK

Member
Looking for the bimetal coil that oprerates the automatic choke on a 69 GMC 350 V8 Rochester 2 barrel carb. Think it is called divorce choke. Seems to be an obsolete part.will try a
pic. If anyone knows where I can find one I would appreciate it. Thanks
 
Mostly called a "choke pull off" Did you try NAPA or a parts store where they still have books and counter guys who can use them. I would think Standard motor products still makes them.
 
Plenty of divorced Rochester choke coils on Ebay. Not called a "choke pull off." The latter is vacuum operated, not by a heat coil.
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I believe a divorce choke could is mounted in the manifold, as others have said, thus is divorced from the carburetor. You adjust it by bending the horizontal part in the rod going to the carburetor.
 
Maybe you already know this but will mention just in case you don't. GM has a port that runs exhaust heat under that choke-coil so it warms up properly. Over time that port gets plugged with carbon and the mechanical coil stops working properly. That is why many got converted to electric-heat assist.

Around 1972 or 1973, GM started started blocking that heat-port entirely for emissions purposes. We took out many of those heat-blocks to make the engines run better when cold.
 
Watch closely on proper spring. Years ago garage rebuilt choke for close friend. Put spring on choke that was laying on bench. Was spring that worked backward to correct carburetor. Engine would run very rich and stall at stop signs. Finally realized choke was closing on warm up.
 
What is wrong with yours? Do you still have the rod? I have a box of those and will look as soon as I can get help to look.
 
I may have that laying around since I have a 69 Chevy pickup out back with a bad block due to no antifreeze in it
 
Because the springs work so good. Pump the pedal twice fire it up and walk away. And no fiddling with a crappy cable.
 
I will take a manual over auto choke any day seen very few that work right . Most of time they run engine to rich and don't want to kick off ( stick).
 
I have rod and cover. Spring is weak and damaged. I think GM part # 3951638. Let me know if you have one to sell. You can call 9182320917. Thanks
 
(quoted from post at 05:42:52 03/15/18) Looking for the bimetal coil that oprerates the automatic choke on a 69 GMC 350 V8 Rochester 2 barrel carb. Think it is called divorce choke. Seems to be an obsolete part.will try a
pic. If anyone knows where I can find one I would appreciate it. Thanks

I looked in some old paper catalogs yesterday, and came up with some X-reference numbers.

Looks like you've found a source, but I'll post 'em anyway, since I have 'em written down.

GM 3951638

GM 3927190

GM 3946093

SMP Hygrade CV23

TOMCO 9015

Carter 170-627
 
Biggest difference on the GM chokes of that era was that some operated backwards from the others. A properly operating GM choke will set with one pump of the gas pedal. Turn the key and it fires up. 30 seconds later, jab the gas pedal and it should drop to it's next step on the fast idle cam. 2-1/2 to 3 minutes longer, when the the accelerator is jabbed again it should drop to a normal idle speed. The choke pull off can be easily checked by removing the vacuum line and depressing it. Place your finger over the vacuum port. It should stay collapsed. If not, it also needs replaced. Now if the choke its self appears to cool off too fast or takes too long to warm up, then it is time to pull the intake manifold on that small block and clean out the carbon stuck under the intake and above the splash pan. That splash pan is held in place with 4 twisted rivets. You will need a cold chisel at a 45 degree angle and a very gentle tap or two to lift those rivets to be reused.
 

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