polarizing turns engine over
 

Of course I did not read the directions and did not polarize the new voltage regulator before I started it. It was reading 12.9 volts running full throttle and 12.7 with the engine off. I tried polarizing after this and when I jump the gen and bat terminals the engine turns over. Is this a good indication that the regulator is fried?

Could be fried, but you've either got the wrong V/R or have it hooked up wrong. Grab a wiring diagram from the tech library and check it.

Voltage regulator part number is napa VR898SB. I have a cub 100 but it does not appear to match the diagram of a 100. It does not have the on switch with a the separate push button to start. Just one keyed switch to start it. Someone may have altered it through the years. It matches the wiring diagram of a cub 102. The regulator I have has F, Bat, and L on one side and has Gen on the other side. I have everything hooked up to that diagram and L has nothing attached to it. Any suggestions? Thanks

That should be correct according to the diagram. In that case, I would first take the cover off of the V/R and make sure one set of contacts hasn't welded themselves shut, and then start looking for shorted wires or incorrect wiring. You already know that the wiring isn't stock, so who knows what all the PO did wrong. It seems most of the people that try to rewire these things don't know what they are doing. Get out your multimeter and start tracing wires to make sure it is what it looks like. I have had tractors where wires were replaced somewhere in the middle of the harness with different color wires that were the same color as was already used in the harness. That makes for some confusion.

And technically, the V/R should polarize itself because it is used on a starter/generator system, but I have heard it doesn't always happen.

Just removed the wiring harness and checked everything. Doesnt seem to be anything wrong. I cleaned all the contacts and made sure for proper ground. I took a voltage regulator off a running cub and tried to polarize it. As as soon as I jump the A/gen/blue wire to the bat wire it starts to turn the engine over. I have the blue wire connected to the back of the regulator which is not labeled. The other 3 wires are labeled and I am not using the L terminal.

If the batt terminal on the voltage regulator always has power and you are suppose to jump the batt terminal to the A/gen terminal then wouldnt it try and turn it over since that is where the large red power cable goes to turn the engine over?

so confused. Maybe im just not reading things correctly.

The correct NAPA V/R would be VR896SB.

:bigthink:
Are you saying, that instead of a "Push-to-Start" switch, your tractor has a Starter Solenoid..??
:Huh:

Yes it has a solenoid instead of the push to start switch. I did not know this was incorrect at the time of purchase.

Attached, is a 70/100 Wiring Diagram modified for a Starter Solenoid....

Wire as per this diagram.

I will take another look today as I do not have the push button and just a key that activates the starter solenoid.

I am just confused that if you are suppose to jump the gen and bat terminals it seems you are basically putting power to the starter and it would turn over.

The modified diagram has NO push to start switch in it.

I have no clue why you are keep wanting to do this.:HeadScratch: