I have a 48 m farmall that started about a year ago and ran perfect for about 15 minutes then just shut off. I parked it and have just now had time to try to get it started. it is the magneto model. I have replaced the battery, cleaned the points, plugs, cap, and rotor. Checked the gap on the points and plugs, tore down the carb completely and cleaned it and reassembled it with the same settings. I have checked the fire at all 4 plugs and have a good spark. I had a friend help pull it off for about 10 minutes but it wouldn't hit a lick....did backfire a few times. Any ideas? trying to get it ready to sell
- Thread starter Rjbsj
- Start date
Anonymous-0
Well-known Member
Since it sounds like you got spark - run down fuel. Make sure there is good flow flow the tank to the carb.
Thanks, I took the line loose from the carb and fuel ran freely from bowl to end. The inlet screen is clean also. I loosened the test cock on the bottom of the carb and the bowl had fuel also.....I haven't checked to see if I have good updraft vacuum though. If I don't, how is this corrected
Anonymous-0
Well-known Member
I'm not real familiar your particular tractor, but check and make sure air intake isn't plugged. Also I recommend posting this on the Farmall site.
Janicholson
Well-known Member
If you happened to get the rotor out of time with the distributor cam, it will not run, and may backfire. I assume you have the cap wired 1342 from the front of the engine.
The rotor must line up with the cap tower just before snapping the impulse coupler. If it is not that is the issue. Jim
The rotor must line up with the cap tower just before snapping the impulse coupler. If it is not that is the issue. Jim
Sounds like you have two if not all four sparkplug wires switched.
I can tell you which way your magneto/rotor turns but it would be best for you to remove the magneto cap and crank the engine over and watch for yourself which way the rotor turns, then put your wires on the cap in the correct firing order in the direction of rotor rotation.
I can tell you which way your magneto/rotor turns but it would be best for you to remove the magneto cap and crank the engine over and watch for yourself which way the rotor turns, then put your wires on the cap in the correct firing order in the direction of rotor rotation.
Brent Zappe
Member
I had a 1951 farmall M. Which use to give me the same problem and it was a magento set up to. What I had found out was that I had the Magneto in right but the gear that drove the rotor was marked to be 180 dergess off. Which meant the rotor was set to fire on the #4 cylinder and it should had been the #1 cylinder. Take the cap back off and turn the rotor gear so it is set to fire on #1 cylinder. before doing this make sure you are on the #1 cylinder timeing then check rotor to the dist. cap and see where the rotor is. Set you rotor to fire on top dead center on #1 cylinder. I thnk that might do it for you okay.
Hold your hand over the throat of the carburetor while a helper makes an attempt to start the engine. See if there's good suction on your hand.
Low suction means low intake manifold vacuum. You need good vacuum to pull that atomized fuel into the combustion chambers. Also remove No1 sparkplug near the radiator and bring that piston to TDC on the compression stroke, then look at the rotor to see where its pointing. It should be pointing to your No1 plug wire that's near 2 o'clock and your plug wires should be in this firing order as your rotor rotates CW:
2-1
4-3
Do a compression check and compare the readings as low compression is a sign of low vacuum. Hal
Low suction means low intake manifold vacuum. You need good vacuum to pull that atomized fuel into the combustion chambers. Also remove No1 sparkplug near the radiator and bring that piston to TDC on the compression stroke, then look at the rotor to see where its pointing. It should be pointing to your No1 plug wire that's near 2 o'clock and your plug wires should be in this firing order as your rotor rotates CW:
2-1
4-3
Do a compression check and compare the readings as low compression is a sign of low vacuum. Hal
Thanks everyone. It was out of timing somehow. I found TDC and aligned the timing mark on the crank pulley and the rotor was pointing to the #2 position on the cap. So I pulled the magneto cover off, realigned to the #1 spot and it fired right up and ran smooth. Thanks again
Janicholson
Well-known Member
I just had that feeling. Jim
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