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Jim/GA · 04-09-2020, 10:09 AM

Take the air filter off until you figure things out.

Backfire out exhaust pipe is from unburnt fuel. You are running too rich or your spark is weak or irregular (cutting off and on).

Most reproduction carb jets that I have seen are too big, result in running with the GAV closed, not open extra. If your engine runs rough with GAV less than 3/4 open, you have another problem. That rich mixture is compensating.

Is car 12 volts or 6 volts? Positive or negative ground?

What kind of coil are you using? Does the coil have + and - markings next to the posts?

Did you wire everything related to ignition exactly as Ford originally wired a Model A? Pop-out switch? Modern or original style points and condenser?

How have you connected the lower plate inside the distributor to the upper plate? Wire? "Improved" wireless contact?

Have you done a compression test on each cylinder? Please post 3 numbers for each cylinder and they build up when cranking with starter, on warm engine if you can.

We can help you figure this out.

04-09-2020, 10:09 AM	#8
Jim/GA Senior Member Join Date: May 2010 Location: Young Harris, GA Posts: 1,819	Re: 1930 82b Take the air filter off until you figure things out. Backfire out exhaust pipe is from unburnt fuel. You are running too rich or your spark is weak or irregular (cutting off and on). Most reproduction carb jets that I have seen are too big, result in running with the GAV closed, not open extra. If your engine runs rough with GAV less than 3/4 open, you have another problem. That rich mixture is compensating. Is car 12 volts or 6 volts? Positive or negative ground? What kind of coil are you using? Does the coil have + and - markings next to the posts? Did you wire everything related to ignition exactly as Ford originally wired a Model A? Pop-out switch? Modern or original style points and condenser? How have you connected the lower plate inside the distributor to the upper plate? Wire? "Improved" wireless contact? Have you done a compression test on each cylinder? Please post 3 numbers for each cylinder and they build up when cranking with starter, on warm engine if you can. We can help you figure this out. __________________ Jim Cannon Former MAFCA Technical Director "Have a Model A day!"