Backfire all the way home
 

I drove my ‘41 from the storage unit to home about 4 miles, once warmed up it backfired all the rest of the way. It also backfires while it idles. I had Skip rebuild the coil and Charlie NY do the carb two years ago, Tubman condenser, helmet has not been touched. Previous owner put new plug wires. I suspect a valve hanging up as the Reds headers have the paint burning off the driver side but not the passenger side. I have a vacuum gauge and a pressure gauge to check fuel. It has an electric pump and mechanical pump.
As soon as it stops snowing:( I’ll get it out into the driveway to trouble shoot).
Is there a checklist of where to start?

Re: Backfire all the way home
 

Faulty condensor if I was a betting man.

Re: Backfire all the way home
 

>>>I suspect a valve hanging up as the Reds headers have the paint burning off the driver side but not the passenger side.>>>


Do you mean a backfire sound or pop from raw gas igniting in the exhaust system, not back up thru the carb? Jack E/NJ

Re: Backfire all the way home
 

Sounds like thru exhaust.

Re: Backfire all the way home
 

I'll take that bet!:D

Re: Backfire all the way home
 

First step--CHECK COMPRESSION all cylinders.

Re: Backfire all the way home
 

8n,
Keep me posted here or at [email protected]
Charlie ny

Re: Backfire all the way home
 

Me too!

Re: Backfire all the way home
 

Run a QT of MMO or AT fluid thru it before you try anything. KISS

Re: Backfire all the way home
 

A back fire is where the fire comes back through the intake plenum and carburetor. An after fire is where fuel gets past an exhaust valve and ignites in the exhaust with a loud report. A sticky valve or more is generally the cause. Engines don't like to set for too long. MMO down the carb with some in the fuel might do the trick.

Back fire is generally caused by a lean condition in the carburetor. Occasionally a carbon tracked or cracked distributor cap can cause a cross fire to the wrong cylinder at the wrong time. A bad condenser generally causes a miss fire of one or more cylinders with poor or no idle.

Re: Backfire all the way home
 

Clean and check points for gap. Run Carb Cleaner through carb also.

Re: Backfire all the way home
 

So I did a compression test
Drivers side 75,80,80,80
Pass side 75,95,85,75

It was as the car sat since I drove it home, I did not oil the cylinders ahead of time.

Re: Backfire all the way home
 

Here’s what my plugs look like.

Re: Backfire all the way home
 

Mixture rich. Clean plugs and it'll prolly run fine again. Jack E/NJ

Re: Backfire all the way home
 

Basic mechanicals seem adequate. Missing is likely ignition related problem. Plugs are indicating miss firing or over rich condition.

Re: Backfire all the way home