This may get a little lengthy but I've done my best to research the forums and I've replaced several things and I'm no closer to fixing my tractor. I'm capable of replacing most parts on a tractor but diagnosing and electrical are not my strong suit. I have a feeling I'm dealing with an electrical problem but not sure.
My 1958 860 was 12 volt converted by a previous owner. It's been a good runner until recently. After a big snow storm in Minnesota I was moving snow for the better part of a day on and off. I took a break at one point and when I started the tractor the next time, it began running really rough, backfiring frequently. I did put some fresh gas in it just prior to starting but I'm skeptical I have bad gas, but I guess I can't rule that out.
I'm assuming it's electrical because I began looking into the electrical components and found several problems. First I replaced the spark plugs with autolite 437s and gapped to .025. They were quite dark with a bit of buildup and I believe gapped wrong at .030. Then I replaced the cap and rotor as well as sanded the contact point in the distributor. Everything seemed to be in working order with the distributor. The distributor definitely didn't move and I made sure the new cap was aligned correctly. Next, I replaced the plug wires. The old ones had a great deal of corrosion so I was hopeful this may have been part of the problem. When removing the coil plug from the coil, it was basically melted on the coil end with no signs of the crimp connector. Assuming the coil was fried, I replaced it with a 12v one from napa and also installed the corresponding resistor since I didn't get an internally resisted coil. It might be worth mentioning that the old coil read "6V" and "use without external resistor" but there was a resistor wired to it. I have a wire from my ignition going to the resistor then to the positive terminal on the coil and the negative going to the distributor, per the 12v conversion post by John in LA from 2004. I was reading conflicting posts (or maybe I'm misunderstanding something) which way the +/- wires go but I've tried both ways with no change. I'm sick of reading about coils and resistors...
At this point I was confident I replaced some obviously bad parts, but it still wont start. It cranks but rarely starts. There's been a time or two where it starts with little effort, like normal, then immediately dies. Doesn't matter where I have the choke. If it manages to run longer, its rough, backfiring frequently. And if I can manage to increase the throttle, the amp meter climbs (alternator starting to charge), at that exact moment, it dies. This lead me to look at the alternator and research the single wire vs 3 wire alternators...
Turns out I have a delco three wire alternator but there is only the one + wire running the the starter solenoid. The other two terminals were soldered together and capped off. They essentially made it a 1 wire alternator but did they do it in a legit way? I know one wire alternators will only charge above a certain rpm so that's what I'm seeing on the amp meter when I increase the throttle. But why does it die when it starts charging? I was thinking of replacing the starting solenoid and maybe wiring the alternator for three wire. I do have an ignition switch with accessory position so I think it would be pretty easy without the need for a diode. But is it necessary at this point? I just want the thing to run again.
I did remove the carburetor and gave it a good cleaning, made sure the floats still float and the settings were correct and reinstalled it with no noticeable improvements. I have a newer fuel tank with newer screen, and I didn't see much in the sediment bowl or in the carb itself. I could get a rebuild kit, but something tells me this isn't a fuel problem.
Any help would be appreciated!
My 1958 860 was 12 volt converted by a previous owner. It's been a good runner until recently. After a big snow storm in Minnesota I was moving snow for the better part of a day on and off. I took a break at one point and when I started the tractor the next time, it began running really rough, backfiring frequently. I did put some fresh gas in it just prior to starting but I'm skeptical I have bad gas, but I guess I can't rule that out.
I'm assuming it's electrical because I began looking into the electrical components and found several problems. First I replaced the spark plugs with autolite 437s and gapped to .025. They were quite dark with a bit of buildup and I believe gapped wrong at .030. Then I replaced the cap and rotor as well as sanded the contact point in the distributor. Everything seemed to be in working order with the distributor. The distributor definitely didn't move and I made sure the new cap was aligned correctly. Next, I replaced the plug wires. The old ones had a great deal of corrosion so I was hopeful this may have been part of the problem. When removing the coil plug from the coil, it was basically melted on the coil end with no signs of the crimp connector. Assuming the coil was fried, I replaced it with a 12v one from napa and also installed the corresponding resistor since I didn't get an internally resisted coil. It might be worth mentioning that the old coil read "6V" and "use without external resistor" but there was a resistor wired to it. I have a wire from my ignition going to the resistor then to the positive terminal on the coil and the negative going to the distributor, per the 12v conversion post by John in LA from 2004. I was reading conflicting posts (or maybe I'm misunderstanding something) which way the +/- wires go but I've tried both ways with no change. I'm sick of reading about coils and resistors...
At this point I was confident I replaced some obviously bad parts, but it still wont start. It cranks but rarely starts. There's been a time or two where it starts with little effort, like normal, then immediately dies. Doesn't matter where I have the choke. If it manages to run longer, its rough, backfiring frequently. And if I can manage to increase the throttle, the amp meter climbs (alternator starting to charge), at that exact moment, it dies. This lead me to look at the alternator and research the single wire vs 3 wire alternators...
Turns out I have a delco three wire alternator but there is only the one + wire running the the starter solenoid. The other two terminals were soldered together and capped off. They essentially made it a 1 wire alternator but did they do it in a legit way? I know one wire alternators will only charge above a certain rpm so that's what I'm seeing on the amp meter when I increase the throttle. But why does it die when it starts charging? I was thinking of replacing the starting solenoid and maybe wiring the alternator for three wire. I do have an ignition switch with accessory position so I think it would be pretty easy without the need for a diode. But is it necessary at this point? I just want the thing to run again.
I did remove the carburetor and gave it a good cleaning, made sure the floats still float and the settings were correct and reinstalled it with no noticeable improvements. I have a newer fuel tank with newer screen, and I didn't see much in the sediment bowl or in the carb itself. I could get a rebuild kit, but something tells me this isn't a fuel problem.
Any help would be appreciated!