Rochester Quadrajet Woes

[Bextreme04]

Thanks. I'll look into this. I bought a rebuild kit already, but I'd hate to find that out once everything has already been disassembled! Since you have already completed the process of changing to electric choke, is there anything that needs to be blocked off or redone vacuum-wise when switching to an electric choke version, or do just need to wire up the electric choke to a ground plus a key-on power wire and then install everything else normally? I thought about upgrading to one with electric choke, but I don't want to make things worse by getting it wrong.

The electric choke conversion for your Q-jet just replaces the thermostat bolted to the manifold with an electric one. You don't actually change anything on the carb itself.

https://quadrajetpower.com/electric-choke-conversion-kit-chevrolet-350-400-71-78/

 

[Normmus]

Thanks. I'll look into this. I bought a rebuild kit already, but I'd hate to find that out once everything has already been disassembled! Since you have already completed the process of changing to electric choke, is there anything that needs to be blocked off or redone vacuum-wise when switching to an electric choke version, or do just need to wire up the electric choke to a ground plus a key-on power wire and then install everything else normally? I thought about upgrading to one with electric choke, but I don't want to make things worse by getting it wrong.

I just did this last week on my '77. You are correct, there is a ground wire and a power wire, which was recommended to connect to the wiper motor wire. And of course the electric choke itself which mounts to the manifold. Nothing needs to be changed vacuum wise. I had been having choke problems with the divorced choke thermostat even after replacing it with a new part. The electric conversion seems to be working much better.

 

[Bennyt]

If, after you've sorted everything else out, you still want to buy a new carb...check out carburetors unlimited in Peoria, AZ. He only does Quads and been in business 40-50 years. I'm very happy with his work.

 

[Bextreme04]

I just did this last week on my '77. You are correct, there is a ground wire and a power wire, which was recommended to connect to the wiper motor wire. And of course the electric choke itself which mounts to the manifold. Nothing needs to be changed vacuum wise. I had been having choke problems with the divorced choke thermostat even after replacing it with a new part. The electric conversion seems to be working much better.

To mimic the OEM electric choke trucks, it is recommended to wire that through an oil pressure switch. This will only provide power to the choke to pull it off when the engine is running. If you just run it through the ignition power you can't sit for any amount of time with the key on and engine off or you will kill the battery and it will pull the choke off without the engine actually being warm. You can thread it directly in place into the NPT hole right above the oil filter in the drivers side of the block. Depending on the engine, you might have a 1/8" NPT or a 1/4" NPT hole there. PS126 is the 1/8" switch and PS144 is for 1/4". You basically run the power however you want, then run the ground to one terminal of the switch and run a wire from the other terminal to a good ground location.

 

[WebMonkey]

Thanks. I have a rebuild kit and I have considered going that route. I'll check out the company you mentioned. I may buy a reman unit just to get it moving again quickly, and then rebuild the one that that is currently installed as a backup if I can determine that it is a real period-correct Q-jet. I like things to be as close to original as possible. I'm just not an aftermarket / performance guy. I feel like you change one thing and then you end up having to mess with everything.

the divorced choke is a good sign it's the 'right time frame' quadrajet.

my '85 uses an electric 'all on the carb' choke.

i agree that not firing on ether or dribbled gas down the throat points at an ignition problem.
maybe in addition to a fuel delivery issue.

(my truck came with a clothespin holding the primary open)

good luck
'monkey