The Stovebolt Site Forums The Shop Area Engine Shop 55' Rochester carb runs 45 sec, the dies

To whom it may concern:
IF YOU ARE POSITIVE YOU ARE NOT JUST OUT OF GAS!,

1. Take off gas cap and test motor. Still stalls? Then:
2. Check squirt in throat of carb, after dying. Not running. Report.
3. Check flow. Disconnect at carb, disconnect coil so it won't start, crank motor, observe how much volume and how strong the pulse is...into a container. I think Jerry did not mean to say "at idle". If Jerry did mean at idle, I don't do it that way.
4. If above test shows good, report here and move to next step. If that test shows insufficient flow, hook hose from can to pump inlet and observe outlet again. still insufficient? bad pump. If flow is good after hose from can, there is an upstream block.
No. 2, 3 & 4 is with motor not running, just cranking.

(P.S. JW51, I did confuse the testing. You can run the motor with truck sitting in the driveway from a gas can sitting on the ground. With pump outlet still attached to carb. This is usually done when checking a truck you want to buy that has been sitting for years. To see if it will run without sucking in bad gas. NOT in this case. In this case it's not for running, but to isolate the upstream flow and prove it's the pump or carb or neither)

If tests show flow is good and you see squirting in throat, probably not fuel delivery.
Put all back together and
Then check vacuum for leaks, be sure there are no vac leaks.
Vacuum leaks:
1. At carb base
2. At carb spacer
3. Intake manifold gaskets
4. Any carb or manifold port, fitting or hose
5. Make sure exhaust manifold heat flapper is not stuck
6. Wiper hose leak
7. You can use gauge, carb cleaner or propane as a detector. Wait for instructions on this if you don't know.

All good?:
Then check timing and begin thinking spark problem/loose ignition wire somewhere. Bad battery or charging. Choke closing.



Some of the advisors have a different sequence of troubleshooting and different ideas of what is wrong. This is normal and healthy. Using a different way of figuring it out is OK and may be a faster track. This is just what I think I would do, without being there. The goal is the same from all of us. We go buy what a poster says, their answers to questions and a feeling we get about the issue. It's always based on good fuel/air, spark, compression. Because it runs, kind of good, then dies, but "backfires, does not seem like timing at this point. But never sure. Agree Must check sooner or later. "Backfire" is also a vacuum leak. Backfire is a very subjective word.