SOS I need help badly - starter elecrtical problem

Joe

I also forgot to note that I found a burned wire in the original voltage regulator from what appears to be water leakage under the cover seal. I exchanged that out. Could it have damaged the windings on the generator/starter motor?????

Thanks for all of the help. I know I can fix this, I fix things that are a lot more complex and that's what makes this so frustrating....

Make sure you can turn the engine by hand. Using jumper cables from a good battery or vehicle, connect the negative to ground and touch the positive clamp to the A terminal on the Motor/Generator. It should crank the engine. If not loosen the belt and see if the unit will spin with no load.

Battery voltage hasn't mattered too much to the problem but I'll charge it up overnight.

I'll try the jumper cable trick and see what it does. If I charge the battery back up to 12.5+ volts again, can I use it out of the tractor with the jumper cables?

I remember having an IHC Scout that wouldn't STOP cranking when I turned off the key. I had to jump out and pull the neg cable (I left it loose). Replaced the starting switch on top of the steering column at least twice. Eventually found that my knee had bounced up into the fuse block and bent two of the fuse holders together so I had a "circuit" where I shouldn't have. Hope this problem shows itself soon.

I am not familar with the switch on your Cub but if one side is coming from the battery and the other goes to the start/gen, then shorting across those two terminals should cause the starter to spin.

You can use your voltmeter to test for voltage drop along the circut. If in the start position you only have .06 volts at the A terminal on the gen/starter, I would just hold it in that position and start checking all the circuts. Start by making sure you still have good battery voltage in the start position. Checking each wire and connection you shouild have no more that .1 volt drop in any wire and no more than .2 volt across any switch. Either the Generator A terminal will have battery voltage or you will find the open circut. Do not overlook the ground path. In the start position there should be be no more than about .2 volts between the gen housing and the neg battery post. If the battery voltage is still over 12 volts with starter engaged you will find some place where there is a big voltage drop.

I'll recharge the battery today and dig back into it. I'm a lot more mechanical than electrical but I can usually sort this stuff out and it's become a "time magnet" lately. I've been reminded that I have a wife and kids that need some attention once in a while too.

I'm not parting it just yet, I need to step away from it for a while. I'll report back what I find.

thanks again

thanks for the suggestions.

One last thing I didn't mention, my replacement voltage regulator has different markings than the original and the tangs are arranged differently across the VR than the schematic shows. I have L F and BAT instead of BAT GEN and F. If I wire F from the generator terminal to the F on the voltage regulator I get a huge arc when trying to install the neg cable on the battery post. I actually have a small weld bead on the neg post from this, which is not good. It did not damage the VR or blow the inline fuse. I rechecked the schematic and compared old and new VR's to see the difference. Right now, I have F on the gen to L and I get a slight sizzle from the neg post instead of an arc. I'm going to get another VR from a local Cub part-out place but I'm thinking the starter relay should at least click so that's what I'm chasing first. What acts as a ground for the motor generator? There's one on the schematic and one for the VR to the generator body (I cleaned the paint off of the generator body under the VR saddle to be sure I had a ground). Would some photos help you guys see what I've got? I can take some and post some links). Thanks

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I've had every connection on the voltage regulator, generator, and all components behind the dash apart, cleaned, sanded, and tightened. I've swapped out most all of them as a test, except the starter/generator itself.

The most I have been able to see flow between the output of the starter switch and the input of tne generator is .06v. If I had a cable ground between the switch and generator, I should see voltage leave the switch even if it returned via the frame or block, but nothing leaves the switch.

I keep thinking it's something simple and that's what has kept me going for weeks, but I can't find it and it's wearing me down.....say nothing of the wife's delight at me spending all of those hours out messing with it. I probably have 30 hours in it so far.....

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