Backfire

[tjeepinit]

As many of you may know I am working on a 1952 VAI. She has been sitting for several years. I have finally got her running. Drove it around. As soon as she sucks all the fuel out of the carb she was shutting off. Light choking kept it running. I took the carb off thinking there was dirt in the line or obstructing the float. Put it all back together and she was well again. A few hours later I went to load it on my trailer and it will not start. It is back firing and coughing thru the carb. Thought it was restricted air so I removed the cleaner. Pulled the valve cover checked all the rods. It still has its original magneto and there is definatly spark. I am lost what could it be she will no start......Thanks as always!!

Tim Fisher

 

[Anonymous-0]

The fuel lines are bad about plugging at the gas tank. Take the fuel line loose from the carburetor to see if you have "good" gas flow. If not, blow back through the line into the gas tank. You might want to consider installing a in-line filter if there is a lot of crud getting to the carburetor. I added both a filter and plastic ball (shut-off) valve upstream of the filter on some of my tractors.

 

[tjeepinit]

Tank is freshly blasted and dipped lines are brand new. First 3 gallons in the tank it has ran through half. Carb was real clean. I had rebuilt that also. When I took apart the carb checking for dirt I didnt see any I assumed I must have missed it when it fired right off when I put it all back together.

Thank you

 

[El Toro]

I would take a look at the mag's cap to see if there's cracks between the contacts. If there's no cracks I would bring No1 piston to TDC on the compression stroke. Then remove the mag's cap and see if the rotor is still pointing to the No1 plug wire. Hal
PS: If its off it may have somehow jumped time.

 

[Walt Davies]

Timing had the same problem with my LA it would backfire on startup and the nothing. reset timing and all was Ok.
Walt

 

[Anonymous-0]

For sure check timing any time you have backfire, check for crossed wires(doubtful since it ran), still might lean toward a fuel problem since it ran while choked. Back check from carb drain, full stream of fuel, fuel line before carb,full flow, fuel from sediment bowl, full flow. Is the impulse snapping, if not may cause backfire as it retards timing to ease starting.

 

[Anonymous-0]

Do you have solid copper plug wires? The only other thing that I can think of that can cause backfiring that hasn't already been mentioned is a bad condenser.

 

[tjeepinit]

Well it appears the reluctant wheels teeth have broke off within the mag. it fires when the tooth catches. anyone have any ideas where to get that "wheel"??

Thanks

 

[tjeepinit]

Would anyone please take a look at this part and help me locate one. I think I would call it a reluctant wheel or gear. If you notice in the one picture it has broken teeth. Its off my 52 Case VAI. I need to find one!! Thanks all

Tim Fisher
broken gear click here