Reply to "Carb backfires"

An engine that is running and the carb suddenly runs dry will backfire.

Generally severe enough to blow out a muffler and possibly enough to put a hole through a piston or bend a valve.

All in the system that would effect fuel delivery to the carb into the bowl should be verified good FIRST.



What are you using for a fuel pump? You need to put a number on the fuel pressure regardless of the type of pump, i.e., mechanical or electric.

Carb needle and seat needs to be verified that it opens and closes. They tend to stick closed after the engine is run and the carb is allowed to go dry by evaporation from sitting. That takes only a couple of weeks.

The float needs to be verified that it hasn't collapsed. The brass floats should be changed to the solid plastic nitrofil floats for safety.


After you do all that, then you set the float levels ACCORDING TO THE DIRECTIONS FROM HOLLEY.

Once these steps are done, THEN you look for vacuum leaks at the carb, at the intake manifold gaskets and at the vacuum hoses.

One place to look for a vacuum leak on a Pantera that is rarely mentioned is at the power brake booster.



You can have a defective check valve OR you can have a rupture to the internal diaphragm due to age.

Even the steel vacuum tube that runs under the car could have rusted through.



These are just some of the situations that will create a backfire.

There are more. You can have a cross wired spark plug wires, seriously fouled spark plugs (then you need to find out why), and a malfunctioning distributor can cause it under certain conditions as well.



Probably what you should do is make a checklist and go down the list one by one like you would do on an aircraft with your co-pilot?