generator issue#2

Tue Oct 08, 2013 6:37 pm

While I had the hood off, I flushed the radiator and engine. I checked the oil pump plunger and it is okay. I put in the new $96 battery, a different generator, and a new $72 voltage regulator. I polorized the gen. and started the tractor. The ammeter needle pegged to discharge as before. I'm thinking I have a short somewhere. When I pulled the switch, the needle moved just left of center as it should before starting. I will play more tomorrow.

Re: generator issue#2

Tue Oct 08, 2013 9:49 pm

Recaping and thinking out loud (I'm saying this out loud to myself as I type)
New battery, generator, and regulator and generator was polarized.
Pull out the switch and ammeter moves slightly left.
Start tractor and needle pegs left.???????

The answer has to be something that changes when the tractor starts. (Likelyhood that you got two batteries, generators, or regulators with this same problem is pretty slim.)
Wiring doesn't change when you start tractor. So a short seems unlikely. It would be there all the time.
Ammeter toasted or is to small of a rating (OK it would have to be a milliamp meter to be to small for a cub :lol: ) and can't handle the current.

Have to go back to your other post and check but do you have a four position light switch (LHDB) for a cutout wired to your voltage regulator? The voltage regulator determines how much and when it needs to charge the battery and does it on it's own, the cutout "has to be told" by the first two positions of the light switch how much to charge the battery. With a voltage regulator replacing a cutout the wiring has to be changed. Go to the side by side diagrams at the end of this old post http://www.farmallcub.com/phpBB2/viewtopic.php?f=1&t=46125&start=15

Re: generator issue#2

Tue Oct 08, 2013 10:37 pm

Sounds like a fried voltage regulator, or wires reversed somewhere. Is it a positive ground 6 volt tractor? If so, and the ground wire is hooked up negative off of the battery then the voltage regualtor probably fried and the ammeter will do what you notice.

Todd

Re: generator issue#2

Wed Oct 09, 2013 6:17 am

This one is a humdinger in the opposite sense of the word. As I recall you said the charging system was working normal before this situation developed while you were using the tractor. You further stated that you had not done anything to the tractor before it started acting up. What could cause a short upon startup? Disconnect the battery lead to the regulator (BAT) terminal, making sure it does not touch ground and start the tractor and observe the meter.

Re: generator issue#2

Wed Oct 09, 2013 8:21 am

I have a 3 pole light switch, off, dim, bright. I unhooked the bat. lead off the vr, tractor will not fire or start.

Re: generator issue#2

Wed Oct 09, 2013 9:37 am

With the switch on, you need current at the negative terminal of your coil to start and run the tractor. If you do not have current at the negative pole on your coil with the switch on, you need to review the wiring schmatics for the tractor that can be found on this forum. You may wish to check for current both ways at the coil, with the battery wire on the BAT terminal of the regulator and with it off of the terminal. If you have a two relay regulator, you should not need the battery wire on the regulator to run the tractor since the wire to the coil is a separate lead.

Re: generator issue#2

Wed Oct 09, 2013 10:37 am

I have current to the coil only with the bat. terminal hooked up. Unhooked with the switch on, the ammeter does not move. I have continuity between the ammeter from the bat. side of the ammeter to the starter and bat on the vr as does the starter side of the ammeter. I don't know if that means anything.

Re: generator issue#2

Wed Oct 09, 2013 11:23 am

I'm gonna throw in my 2 cents here. It sounds like a dead short in a wire between the generator and the cutout/VR.

Re: generator issue#2

Wed Oct 09, 2013 12:06 pm

Compare this wire diagram with your set up and indicate whether your regulator and generator are wired accordingly. Your wires between the regulator and generator are relatively short, but as Smokeycub says, make sure they are not touching anything between their attachment points. Another test you can run is to remove the wire currently on the negative pole of the coil and temporarly attach the battery lead that normally goes to the voltage regulator to the negative terminal of the coil and start the tractor. This test will supply battery current directly to the ignition system and it will bypass the regulator, generator and starter switch. Note the ammeter reading. You will need to be able to remove the battery lead from the negative terminal on the coil to stop the engine.

http://s101.photobucket.com/user/farmallbob/media/Farmall%20Tractor%20Wiring%20Diagrams/02-6vSHandSMstock-rev04_17_08_08-1.gif.html?sort=4&o=0#/user/farmallbob/media/Farmall%20Tractor%20Wiring%20Diagrams/02-6vSHandSMstock-rev04_17_08_08-1.gif.html?sort=4&o=0&_suid=138132680077509065888122308139

Re: generator issue#2

Wed Oct 09, 2013 1:18 pm

I will try that. I put my other gen. on the tractor. I started it up and the ammeter stayed just left of center on idle. I sped it up and it flatlined to discharge. The needle stayed flatline dis. after shutting the tractor. off. I had to unhook the battery and it went back to center.

Re: generator issue#2

Wed Oct 09, 2013 1:18 pm

I will try that. I put my other gen. on the tractor. I started it up and the ammeter stayed just left of center on idle. I sped it up and it flatlined to discharge. The needle stayed flatline dis. after shutting the tractor. off. I had to unhook the battery and it went back to center.

Re: generator issue#2

Wed Oct 09, 2013 1:28 pm

I have been thinking and studying on this since it first started, and the only thing that is making sense is for the generator to be polarized backwards. The diagram Challenger posted a link to is for the H and M, but is also the same diagram as used by cubs with a factory installed regulator. The lights and ignition are powered from the L lead of the regulator, so the bat lead has to be connected to it for the ignition to work. Time to back up and start again.

First, make sure you are using a 6 volt battery, not a 12 volt battery. This might cause the problem.

First, Second, verify that the + terminal of the battery is connected to the cable going to a ground bolt, and the - terminal is to the cable going under the tractor. Next, use an analog voltmeter and verify the polarity of the battery, yes, they can be charged backwards, but will have reduced life and capacity. If all is correct so far, with the engine STOPPED, briefly jump between the bat and gen terminal of the regulator. A small spark is normal. Then restart your engine. If you have the same problem, check polarity and voltage at the A term of generator, and at the gen term of regulator as well as at the batt term of regulator.

Does it still have the original ammeter, or has it been changed?

Re: generator issue#2

Wed Oct 09, 2013 2:05 pm

I ran the test with the coil. The ammeter stayed 2 marks left of center while increasing the speed. Positive is ground, neg is hot.The ammeter is original, new 6 volt battery. I appreciate everybody"s suggestions. I will try this next.

Re: generator issue#2

Wed Oct 09, 2013 2:53 pm

I have been trying to figure out a similar problem on my recently acquired 1961 Cub. This tractor had sat for years without running until I bought it a few weeks ago. It has done the same thing but not consistently. Slight discharge when I pull out the ignition switch, strong discharge indicated on the ammeter when running. At one point it seemed to be corrected by multiple attempts to polarize the generator and it then showed a positive charge. But a couple days ago when I last I had it running, the ammeter was showing only a slight discharge with the tractor running. I plan to try a different generator and I also suspect that the regulator is not functioning correctly. I will watch this topic in hopes of learning something and post anything I discover.

Re: generator issue#2

Wed Oct 09, 2013 3:14 pm

I verified the battery hookup, polorized again, started tractor, got 3 volts off gen. terminal on gen.and 4 1/2 volts off bat terminal on regulator. The gen., I touched hot lead to pole and minus to a ground, same with bat. terminal. I have wired a house but this ain't a house.