Runs bad

Brian SATX

Brian SATX

Well-known member
Stock except modern points/condenser. Starts fine and idles good. When I try to give it gas in the driveway, it back fires and stumbles. Timing is right, points are good. Any suggestions where to go next?
 
Double check the basics incld fuel condition::
See if your losing spark or fuel... Condenser?
I use an inline spark tester to monitor the spark or carb cleaner to richen it...
 
Last edited:
Aloha,
Had a similar issue, as soon I applied some throttle it would miss and die.
It was a condenser issue.
 
Do you drive the car regularly?

Did it just start doing this with no adjustment, repair or replacement of any other part?

If something was changed just before it started doing this, what was it that was adjusted, repaired or replaced?
 
Brian:

Make sure you have a good fuel flow from the tank. Remove the fuel line and see if there is a strong stream with the gas cap off. Next check your gas cap to see if the vent hole is plugged. If you have a repo 30-31 gas cap with a center rivet it can loosen up and the gasket and the large washer can rotate and cover up the vent hole.

Tom Endy
 
If you were running stock points I would suggest looking for a failing flexible wire under the movable plate in the distributor. However a back fire is often a symptom of an air leak at the manifold or carburetor. Check to see that the four bolts holding the manifold on are snug and make sure the carburetor is tight to the manifold.
 
Sorry a little more info. Not my car, but a friends. He has not driven for a few months. Good fuel flow, spark at points and coil wire. First time working on it yesterday. Pulled what little hair out and found the fuse holder was bad. Got that taken care of and today trying to work on the backfiring. Timing is good, plugs gapped right, points set right. Going back over tomorrow and not leaving till it is right.
 
I've found that most carburetor problems........ are cured by fixing the ignition. Points/condenser, possibly coil.
 
fiddlybits said:
I've found that most carburetor problems........ are cured by fixing the ignition. Points/condenser, possibly coil.
Click to expand...

But every now and then it really is fuel flow and or the carb...

Next crazy thought is if you have a sticky valve in there.
 
Brian SATX said:
Stock except modern points/condenser. Starts fine and idles good. When I try to give it gas in the driveway, it back fires and stumbles. Timing is right, points are good. Any suggestions where to go next?
Click to expand...
first pull the carb apart make sure everything is clean and jets and passages are all clear
just had the same little problem on a newly rebuilt carb. found out i had to have the GAV open a whole turn for it to run right.
so i guess thats where i would go first seeing that car sat for a while with more than likely corn gas in it.
good luck
Tinkirk
 
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