I am Having a problem with my 76 440. It back fires when I start from a dead stop. some times the engine will stall and I will have to press the pedal to the floor and hold it there until it starts back up. seem to do it more when cold. I took auto shop back in high school and think its maybe vacume advance or carb problem. anyone have a better idea whats happening.
What you have is a choke problem it sounds like it's sticking closed and flooding the motor when you push the pedel to the floor it opens the choke up and clears out the fuel so you can get it started, does it do it after it gets hot?
No Jim, it runs fine at normal temp. when cold I will press down on the pedal and let off slowly and it starts fine most of the time. its when i go to drive and give it gas it will back fire and then stall.
Where are you located in San Jose? I live in San Jose and wouldn't mind giving you a hand troubleshooting it. I have been one type or another mechanic for around 30 years, jet mechanic, car, diesel. Let me know on the offer at: NetConnected@hotmail.com
Now it sounds like the opaset the choke isent closeing enoff or is opening up to quick whitch is starving it for fuel then it back fires take Charlie up on the offer but I think you have a minor choke adjustment problem
Jim (//images/smiles/icon_smile.gif)
Sounds like another thermoquad to me (//images/smiles/icon_sad.gif)
Sounds like another thermoquad that needs to be straightened out by some one who REALLY knows the beast. Get it right, then (//images/smiles/icon_biggrin.gif) and its argueably the best possable carburator for your rig.
Bob Chaney
Just rebuilt my Thermo-Quad. It was $35 dollars for the kit and five hours. I think this is my first four barrel to rebuild. 12 separate adjustments. I used Car Quest rebuild kit and they had good directions. I also have the shop service manual for this vehicle and this helps me out a lot whenever I have a problem. The original symptom was a lot of black smoke on startup and sometimes after warm up. I could look down the secondary barrels and see gasoline dripping in while at idle so I knew the float level had to be too high. Think I had a bad float valve needle. These are rubber tipped and deteriorate after a while. There is a stamping on the bottom edge that gives the Carburetor Number. You have to look up the specifications for that specific carburetor that you have, and it can vary a lot. I did not disturb the idle mixture and the idle seems ok, but would need smog equipment to get it just right. This carburetor has metering rods for warm-up and so I though I would back the automatic choke off since it was closed, even at 90 degrees outside air temperature. The book says not to disturb the automatic choke setting. I think I got it too lean because I get a cough for the first few minutes if I step on the throttle hard, but it runs very well after warm-up and I certainly do not have any black smoke.