Ford 801 12v conversion

I've been trying to convert my Ford 801 Powermaster to a 12 volt system, and I've done everything that the article on this site said to do, and used the parts it said to use. However if I touch what used to be the negative ground to the positive battery terminal, it arks and the engine cranks over. I'm not sure what I did or didn't do to cause this and any advice would be great.

Well with out a lot more info and how you have it wired it is hard to help you. But with what you have said sounds like a bad solenoid or a starter switch hooked up worn or stuck down

Check the starter solenoid , If you replaced it either is the wrong one or wired wrong. joe

Sounds like something is wired wrong.

If it's not already too late, disconnect the alternator wire(s) temporarily until you get the wiring sorted
out. This is to protect the alternator from damage.

Once you get it starting and running, then reconnect the alternator. If the short comes back when the
alternator is connected, either the polarity is reversed, or the alternator is damaged.

What is the history on the battery, is it new, used? It is possible for a completely discharged battery to
have the polarity reversed if charged backward. That could cause the arcing, but that would not explain the
starting problem.

The battery is brand new, and as far as how I have it wired, is that I've left everything alone except installing the alternator and replacing the coil with a 12v coil and reversing how it was hooked up ((negative running to distributor)). I first hooked the new 12v solenoid up just like the old one, but still had the problem, so I reversed the battery and starter wire, and still got the same problem.

Welcome to YT, Tyler. I'll see what we can figure out. I typed out the following as a first reply, then got called away to a farm emergency, then promptly fell asleep when I got back in.

As a disclaimer, I don't own a Ford tractor, but I've been loaned a neighbor's '62 851 that was becoming yard art after he got a new Kubota. I also know a little about electrical systems.

Do you have a meter? Around here, Harbor Freight is giving away their 7 function (probably last about 7 uses) meter with coupon. Or perhaps you can rig a 12v test light? Any 1156 or even a 1157 with one good filament with a couple wires soldered on, or in a socket with a couple pigtails would help you sort things out safely.

I'm guessing your tractor had an original positive ground 6v system that you converted to negative ground for use with the 12V alternator, and now when you touch the negative cable to the battery (with the positive hooked up to the solenoid), it cranks and tries to start. Correct? This is dangerous, simply because making a spark at a battery, especially a big spark, can ignite the hydrogen gas a battery releases, and blow it up. My brother had one blow the top off of two cell nearest the terminal he was connecting. Fortunately, only acid on his hand and shirt, and a hose really close by. Always better to disconnect and reconnect the ground at the far end of the cable if there might be ANY load, not at the battery end. First off, I'd remove the ground cable at the frame, connect the battery end (leaving the frame end loose), then go on with testing.

Solenoids and starters (and ignition coils) don't care which way the electricity flows. Alternators do. If you even momentarily goofed up and made the connections 12V + to ground, you've blown the rectifiers in the alternator. In my experience, you do not have to reverse the ignition coil, and in fact, when I tried that as a test on one of my tractors, it wouldn't run. "YAMMV".

If you have the standard Ford starting system with the 5 speed tranny, it has an on/off ignition key with a safety start switch push button that tests the neutral position in the tranny that if all is good, 'grounds' the starter solenoid coil. The solenoid has only 3 terminals, 2 big ones and a small one. The small one should have just one wire on it. There is an internal connection from the 'bat' terminal to the other side of the solenoid coil. If hooked up backwards (battery to the starter side stud), it won't work at all.

You may have a short to ground in the start switch circuit. You can test that by removing the wire from the small (8-32 thread) stud on the solenoid, then touching the ground wire to the tractor 'frame'. If nothing happens, you've found the problem. It may be the wire from the push button switch, or the PBswitch itself. If the solenoid has 4 terminals with a wire going to a coil resistor bypass, you may have the start button wire on the wrong small terminal.

If it still wants to start with the switch wire disconnected, it may be the solenoid is defective, or perhaps that you put both battery and starter wires on the same terminal. A test light from the battery + to the start switch wire (disconnected) should not light up until the start button is pushed (with tranny in neutral). Your test light (or meter) connected between the starter side of the solenoid to the battery ground cable should not light (or show voltage on a meter), until the solenoid is energized.

I hope this is clear enough to follow. Let us know how you make out.

The new solenoid... Is it an automotive solenoid? If so, it's wired different internally from the original. Like Welworn said, the original solenoid uses a ground circuit to energize it. But even that doesn't explain why it would try to crank without getting the proper signal from the starter switch.

You can buy a 12v solenoid from this site for that tractor from this site. It has 4 terminals, the 2 small terminals energize the solenoid. One will wire to the battery side of the solenoid, the other will wire to the start switch, which will complete the circuit ground, energizing the solenoid.

OK, first you can wire a solenoid backwards depending on the design of the solenoid. Disconnect the small terminal wires from the solenoid and see what it does. If the problem persists try taking any wires on the large terminal that are not the batter cable off or swap them to the other large terminal.

2nd: you don't say if it's a one wire or 3 wire conversion. If it's a 3 wire is there a disconnect or diode on the small wire that that comes back to the tractor? That wire can back feed. Most often the problem there is the tractor won't shut off but if wired different it could excite the solenoid.

If you go to the Ford page here on YT there are several people who are very good with electrical problems.

Rick

Okay, so I'm trying to do a one wire alternator swap, and if I just try the battery wire and starter wire, it still arks, no matter which terminal I put them on. Also if I add the two smaller wires it still arks, I'm so confused as to what I've done wrong.

If the battery cable arcs when touched to the battery, (or the other end) and the engine cranks, there is only one thing that can be wrong. The relay (solenoid). when all small wires are removed from that device, it should be an insulator and nothing should get through it. If it does, it is broken. (this includes even the wrong part that looks correct. The one wire setup is simple in that it requires three changes. Bulbs to 12v, coil 12v no resistor required, or 12v resistor required if the original ford system had a resistor wire in the ignition circuit (often pink). The coil needs to be attached with the Negative terminal to the distributor. The last thing is the heavy wire from the new alt (should) go to a 40 amp fuse, or fuse link) then to the positive battery terminal. If you want the amp gauge to work, it needs to go on the load side of the amp gauge. Many of the Ford tractor and early Ford cars had a relay that was turned on by grounding at the starter button. Later ford relays look the same, and are very different, they work by getting 12v to the S terminal. Jim

I went and had the solenoid tested and yes it turns out that it was bad, I didn't really expect that since it was brand new, but they're ordering me another one free of charge. Thank you all so much for your help, and hopefully it'll be fixed once I put the new solenoid on.