Trouble shooting external regulator 12V conversion

It is currently connected as follows

F terminal on the regulator to the F terminal on alternator
“2” terminal on the regulator to the “R” terminal on alternator
“3” terminal on the regulator to the “bat” terminal on alternator and + battery terminal
The case of regulator is grounded, as is the alternator ground lug (and just to make sure I ran an extra ground wire directly between the two).

Various sources (internet, local parts guys, etc) seem to indicate that the above is correct.

I’m assuming that the problem is with terminal “4”. This was hooked to a wire coming out of a tangle that seemed to initially come from an ammeter. 12 Volts never appeared on this input, and the tractor did not charge. When I jump this to 12 volts, the tractor charges. (I see 14 or so volts across battery whereas I see 12.9 when tractor is not running with a fully charged, newish, battery). Of course, if I do this I CANNOT TURN IT OFF. The tractor keeps running when I attempt to shut it down.

Same wisdom sources indicate that I should put a warning light in series with this (so instead of connecting terminal 4 to 12 volts, run it through a light first. A #161 was specifically recommended, so I soldered a pigtail to a #161 and put it in line (measures 9 ohms across my bulb+pigtail before I put hook it up). If I turn on the tractor, the bulb glows, but the tractor does not charge. If I jumper (bypass) the bulb (I’m back to where I was before, and) the bulb goes out, the tractor charges but won’t turn off. If I TEMPORARLY short around the bulb, the bulb goes out (duh), and when I remove the jumper it STAYS out, and the tractor keeps charging, and now I can shut it off.

The question: I’d like the tractor to charge w/out going through these hoops. I’d also like to be able to shut the tractor off. (I realize I can rig up a toggle switch or relay and get this to happen, that’s not what I’m asking. Running this terminal to the starter relay (only hot when cranking) doesn’t work either, the connection gets real hot since the starting motor acts as ground when not engaged). I also tried tying terminal 4 to the bottom of the ballast resistor, with the same effect (charges, but can’t shut off).

Any solution? The previous/current owner has another alternator which checks out fine (according to a local shop), I might swap that in just to see what happens. The voltage regulator is new (and the old one checks out fine). The guy I’m buying it from replaced parts trying to track down the problem. The tractor is at my house now, but I can get the old regulator or the newer junkyard alternator to try them, but that doesn’t seem to be the problem.
Is there a magic resistance that’ll work in place of the bulb above? A better circuit to try? I guess the next step is to check my library for a Pre-71 GM Chilton’s with a wiring diagram, but I got the above hook up from 3 different sources (and it turns out it was what was on the tractor all along w/ terminal 4 being questionable)

Thanks in advance,

Bob Fourney

I stuck a diode inline yesterday. It gets around to charging after a minute or so, and levels off at about 14.3 Volts. It stays above 14 even when I drop it down to idle. Best of all, when I tell it to turn off it does so!

It ain't pretty, and I still need to rip out all the wires and start over (there is about a half mile of wire strung about, lots of questionable connections, etc). The main goal for this week was to make sure all the parts (alternator, regulator) work so I could settle up w/ the seller, I plan to fix the spaghetti wiring "later". Since I tend to procrastinate, I taped everything up nice and zip tied all the (pre-existing and new) wires out of the way.

The ammeter indicates that it's charging, which I didn't expect. (The ammeter working is a bonus)Sometime this summer I'll sort out all the wiring and hook up the lights. I'm still curious to see if (the other) Bob comes up with a circuit that doesn't use a diode or extra switches.

Thanks again for all the help,

BTW, the battery is currently sitting out to the left of the hood, exposed to the weather (well, if it wasn't in my barn it would be). It's in a sheet metal "battery box", but no cover or lid. I was going to rig a wooden lid for it, but last night I was looking at a picture that seems to indicate that the battery should be under the gas tank. If that's true I'll look into moving it (or a smaller one) back underneath. (I haven't looked at the actual tractor for evidence that it was once there)

Thanks again, Bob

If your regulator will not work with power on only #3, try it with power to #2 and 3, as your regulators may be charge indicator spec units.

Where you have been trying to use the 161 light bulb, install a 2.5 amp 1000 PIV diode as follows:

End with white band towards regulator terminal. (This is the CATHODE end of the diode.) This will stop the back-feeding of current to the ignition system, and allow the tractor to SHUT OFF.

I used to use ECG-125 diodes, or NTE-125 diodes for this purpose. Anyhow, a 2.5 amp @ 1000 PIV diode should not be too tough to find, and they're CHEAP!

Another way to do this is to use a 2 terminal oil presure sender that turns on at 5 PSI, or so. Screw the sender into an unused oil gallery hole in the engine that's now plugged, or tee into the source for the oil gauge line. Connect one side to the battery (Using a fuse or a piece of fusible wire in this lead is a good safety feature). Connect the Other pressure switch lead to the #4 terminal of the regulator.

This method will supply power to the charging system with the tractor running, and shut the power off when it stops, without the connection that can feed current back into the ignition system.

When I get to the shop tomorrow, I'll dig up some of my old diagrams, and double check on the wiring you describe. There are many ways to hook up a system like you have, all of which will work, but some are needlessly complicated.

Thanks,

Bob Fourney

I'll look at some diagrams tomorrow. I think the reason your bulb wouldn't do the trick is that with the way your circuit is hooked up, the current into #4 has to keep a relay energized all the time, and the current through the bulb can't hack it. There is a circuit for that alternator and regulator that will allow the use of a warning "idiot" light.

As far as the momentary "push to energize" switch, I believe that applies more to the newer 10SI or 12SI alternators with a built-in electronic regulator.

I am not understanding your last paragraph, about not being able to shut the engine off quickly if the oil pressure drops. My suggestion was to use a new and separate sender from anything that's on the tractor now.

This method WILL NOT backfeed into your ignition system, and will not affect the reading of your current oil pressure warning system, whether it be a mechanical gauge, an electric gauge, or a warning light.

I may have mis-understood what you meant with the oil pressure sender solution. I thought you meant to hook the hot to the #4 terminal via an oil pressure sender. This would be a short circuit/direct connection as I start the tractor, but would become an open circuit once the required oil pressure was reached (2-5 psi for an idiot light switch). Then, when you go to kill the tractor there is no connection and it turns off. My concern (assuming that the above is what you meant) is as follows: Say the oil pump dies, and the oil pressure drops. I notice instantly, and have a snowball's chance of shutting down the tractors before the bearings are lunched, so I promptly push in the igntion switch. Unfortunately, when the oil pressure dropped, it caused the 12V to be directly connected to the #4 terminal (the switch is a direct connection below 2-5 psi). So, I can't shut off the tractor quickly, and I really need to! Sorry if I mis-interpreted your suggestion.

Thanks all for the help. This is my first tractor, so you'll probably be hearing from me with lots of stupid questions.

Thanks again,

Bob Fourney

The sender we use on alternator conversions is the opposite of a sender for an oil pressure warning light. The unit we use is OPEN below about 5 PSI and CLOSES when the engine starts and oil pressure comes up. There is no connection from the sender or the regulator system to the ignition switch, so the tractor will stop anyime the ignition is switched off.

I didn't make it to the shop yesterday, but I'm heading there now, and I'll check out my notes and diagrams and get back to you.