48 Farmall M is Backfiring out of carburetor and exhaust.

[48_Farmall_M_JC]

Hey Im Jc and I have a 48 Farmall M that I just did a tune up on and it is backfiring out of the carburetor and the exhaust. It first was coming out of the exhaust, then we checked the firing order and fixed it, but it still backfires occasionally out of the exhaust, and the carburetor. We have the gap on the point set for .020" but it still won't even give a single pop, just turns over the engine.

If you have any solutions please let me know.

 

[Bob]

Magneto or distributor?

 

[48_Farmall_M_JC]

It has a distributor no magneto

 

[Bob]

Have you checked for a good HOT, consistent spark?

If you've got spark make ABSOLUTELY sure it's timed correctly, not 180? "out" and that the firing order is correct..

If that checks out, do a compression check to find out if a bunch of valves are stuck open.

That being said, when did it last run correctly, has there been a long period of storage and possible rusting?

 

[mmfan55]

Backfire at idle or under load? Idle
likely to be timing, valve
adjustments or sticking, or other
electrical issues. Under load could
be running lean.

 

[48_Farmall_M_JC]

The last time it ran was when I put it in the garage.

 

[David G]

I would suspect plug wires are backwards; what all did you take apart?

 

[48_Farmall_M_JC]

I checked the firing order for the plugs and they are going in 1342 right now.

 

[roy prins]

so You said You checked the firing order and it was correct -- did ya go around the right direction on the distributor -- if Ya didnt it will put two cylinders out of time -- 180 off so to speak -- Roy

 

[Ferd]

Had a gas Oliver that would do that - opened the points a bit and it quit backfiring.

 

[Ferd]

Had an Oliver that would do that - opened the points a bit and it quit backfiring.

 

[David G]

My suspicion is that you have the plug wires 180 off, remember there are two TDC's.

I only pull one plug wire out at a time.

 

[48_Farmall_M_JC]

Thanks ill check over it and see if I can get it to work

 

[used red MN]

In the old post In the link the reply shows how the plug wires should plug in the cap if the
distributor is timed as recommended from the factory. In fact I think the IH dist. caps have the
number 1 plug wire tower marker with a 1. Just to clarify another thing that sometimes is
misunderstood the cylinder nearest the radiator is number one. And the distributor rotation is
clockwise as viewed from the seat. I also have a 48 M.
Old firing order post