Backfire out of the carb?

[MTC_75vette]

Occasionally when I shut off my car the engine continues to turn for a split second and then backfire out of the carburetor occurs...does anyone know what can be causing this? I was told it may be carbon build up inside the motor?

 

[minifridge1138]

I've never heard of carbon build up causing backfire through the carb.

Backfiring through the carb happens when a spark plug fires before the intake valve closes.

Usually it is caused by ignition timing being too far advanced. Reset your timing and the problem will most likely go away.

 

[Rodney Gold]

Could also be your idle speed is a little too high , either reduce it or shut the car off in gear and then put it in park or neutral.

 

[KANE]

Occasionally when I shut off my car the engine continues to turn for a split second and then backfire out of the carburetor occurs...does anyone know what can be causing this? I was told it may be carbon build up inside the motor?

If a mechanic told you that... run away from him fast. It sounds like he wants to charge you for a new motor!

I think it is your timing too. If you have the stock motor, set it to the factory advance and then work your way from there.

It would help to change the cap, rotor, wires, plugs, air filter, fuel filter, and oil as part of a tune up. You also might want to check the setting of the mixture screws too.

Good luck- hope that helps!

 

[SR'71]

If you have points in your distributer it could be your starter soleniod. When starting, your points are powered thru the solenoid with 12V. After the start switch is relaxed the power to the points comes from the start switch thru a ballast resistor reducing the voltage felt by the points to 6 to 8 volts. This might be a parallel path that keeps the engine running.

 

[Vettehead Mikey]

This might be a parallel path that keeps the engine running.

How would you stop the engine then?

 

[6880 Mike]

1. Timing.
2. Carb solenoid not closing all the way.