backfire.

Have you all noticed that we got 1 question and 15 replies now and the Original Poster has not come back to clarify if he meant he was getting a true backfire out the intake throat of the carburetor or if he meant he was getting explosive backfire out of the tailpipe?

We have provided answers to both scenarios, but we still don't really know for sure what the symptoms are!

Or perhaps he has solved the problem and never came back to tell us he found a loose wire, or replaced the condenser. And we are rambling on about float levels, leaky intakes, etc. No criticism to the people who have answered, I'm sure others appreciate reading the ideas.

But as a courtesy to others, some follow up by the original poster would be nice.

.

"Doctor, I feel sick. What's wrong with me?"
 
Want to have fun. Drive at a moderate speed and turn the ignition off while in gear with the clutch out. Wait several seconds then turn the switch on. You might want to be wearing depends for this. Also you may have to replace the muffler.
 
Want to have fun. Drive your "A" at a moderate speed then turn the ignition off coasting in gear with the clutch out. Wait a few seconds then turn the switch on. Be prepared to replace the muffler.
 
Want to have fun? Drive your "A" at any speed. Be prepared to have lots of people waving at you and smiling. :) . Arrive home feeling great!

The End
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Want to have fun. Drive your "A" at a moderate speed then turn the ignition off coasting in gear with the clutch out. Wait a few seconds then turn the switch on. Be prepared to replace the muffler.

A friend of mine in high school in the late '50's used to do that in his dad's Plymouth with an automatic transmission. He claimed that his dad drove the car too slow and he was cleaning out the carbon!

He did that once too often and we got picked up for disturbing the peace and spent an hour at the substation before they let us go.

David Serrano
 
GAV - Gas Adjusing Valve.


It is used to adjust idle fuel air mixture when teh motor is cold and while the Motor is warming up.


The Choke/GAV Rod adjustment is the knob under the dash on the passenger side of the A.


Pull the knob/rod out for full choke to prime the motor for starting. after a couple of motor revs using the starter push teh rod in and the motor should fire/start


GAV fuel/air mixture is adjusted by twisting the knob/rod from full clockwise, turning it CCW. Depending on the A for starting a cold engine typically it is turned 1/2 - 1 turn CCW. As the motor warms turn it clockwise. for best idle/running.


There is info on this in the Model A owners/user manual.


Lots of detailed carb info on this site.
https://www.model-a.org/gav_seat.html
 
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