help!model a backfiring/missing

W

winchets

Junior Member
went for a drive today and the model a lost power and was missing and backfiring.

If i drove slow the problem was less. I have not checked the plugs yet or the compression but I plan to do both just not on sunday...Ive got enough problems with out working on sunday:)
 
Two things that helped me were a new condenser and some MMO in the fuel to lube the valves. I am thinking it is the condenser as mine would sputter and backfire when it was on its way out after it got to hot.

Mike
 
Did you just take it out of storage? If so you may have a critter nest in your exhaust system causing back pressure.
 
As well as the condensor ,maybe your timing is way out, check the points gap,also distributor shaft can have sideways play in it if the bushings are worn , that throws the timing out!!!
I have even seen an upper plate that had the the pin for the points broken off at the base , allowing the points gap to move around it caused a lot of backfiring!!!

John Cochran
 
If it seems worse a the speed/power demand increases and will run better when slower, the problem could also be fuel delivery. Such as, gas cap vent, restricted fuel line etc.
 
I had the same problem with our a a few years ago. It was a warped intake manifold. We replaced it and have had no problem
 
Gummed up jets from storage, condensation in gas, critters in exhaust...A lean condition will give the symptoms you describe. Remember, eliminate the simple first...nothing major happened while it was in storage in all likelihood. Distributors didn't wear out, manifolds didn't warp while it was sitting idle
 
Dog:cool: here, Why don't you check sum stuff, 'afore you ask us, we AIN'T MAGICIANS:eek: Whin it's runnin' BAD, gradually pull the choke on, if it gits BETTER, it's too lean! If so, jist o'haul thu carb.
Buster T.:cool:
 
thanks for the laundry list of things to check. I asked first because I DIDNT know where to start. I am brand new to model a's. if it was a snowmobile it would have been fixed by now. The trouble seemed to start last summer after a parade, it got hot and did the same thing. later it seemed ok but all i do is drive around the neighborhood so no real load on the motor. I will check a few things this week. I did just pull it our of storage but we run it yr round and its in a heated garage.
 
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Let us know how your checks go. This is a great site to ask these kinds of questions. Don't worry about some grouchy responses! : ) We all do want to help, just different styles of delivery. Keep asking!!!
 
When it's missing & fartin', look at it in the DARK, sometimes the dist body can ARC out the top, to a plug strap. It's usually the track to #4, arcing to #3 plug strap. Minerva farted out once, KABOW! KABOW! I used a strand of woven closeline wire, for a strap, arched it up HIGH, so it couldn't arc out & ran O.K. for a month, 'til I got a new cap. Chief taught me that "TRICK"----Bill W.
 
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