100 Starting Issue

litlmikeyl · #1 01-26-2013, 11:04 PM

My 100 has been getting harder & harder to start as time has passed. The engine itself is fine - turns over & runs like it should. My issue seems to be in the electrical system somewhere. I turn the key, push the button and nothing happens. Before I could do those two things simultaneously and try to "bump" the S/G pulley with the palm of my hand forcefully and the engine would turn over. The S/G would seem like it had caught (similiar to getting past a dead spot in an electric motor) and keep turning the engine over, and the engine would fire up shortly after. Now I can't even do that.

I rebuilt the start button - cleaned the copper contacts inside, the tractor has a new Porch Electric harness, the voltage regulator (that isn't adjustable as far as I can see) is supposedly about 5 years old as is the S/G according to the PO. The battery is a 625 CCA Group 26 car battery and that's only a couple of months old. The battery cables are automotive type 4 gauge size that were replaced when the new harness went in. All of the wire contact points has been checked and are all tight and clean in condition.

So far, here's what I've figured out...

If I hook up jumper cables to my truck (both directly on the battery, truck not running) and connect the negative clamp to the ground cable, which is attached to the rear mounting bolt of the S/G, and the positive to the "A" terminal on the S/G, the S/G spins like normal with no hesitation. With the tractor running, I am reading battery voltage on two terminals on the voltage regualtor - the gray wire and the green wire. This last time I ran the tractor I was getting a voltage reading of 10.22V. When I would try to turn over the tractor without other aid, the battery voltage would drop to a very low amount (which I don't remember exactly what it was) though nothing mechanical would happen. Every time I've run the tractor the battery voltage has dropped a little bit and hasn't recovered, which leads me to believe that the battery isn't being recharged by the tractor.

I did find and read thru the Delco Remy service bulletin on cabfaq's website about how the S/G is supposed to work and how to troubleshoot it but even after reading that I'm still confused on how to correctly troubleshoot it. Also, I don't have the specialized tools that the procedures call for; I only have a standard issue Craftsman digital mulitmeter in my arsenal.

Not sure what to do next, except charge the battery back up again. Curious as to what you guys think - I'm still learning how this electrical system works.

Yosemite Sam · #2 01-27-2013, 12:13 AM

Sounds like it isn't recharging the battery. Check voltage across battery terminals (should read 12.6 to 13.4 or there abouts).

If it is low (and if it were mine) I would loosen the S/G and take the belt off and let it hang on the crank shaft pulley. Get a "jumper wire" and connect it to the "F" terminal on the S/G... While spinning the S/G with the starter button on the tractor, ground the "F" terminal directly to a known good ground (preferably right to the S/G case). The S/G should slow down noticeably while being grounded, if it does not slow down then the S/G is defective and should be serviced or replaced.

If the S/G shows to be good, then I would move on to the voltage regulator or wire loom.

Please understand that, just because a wire loom and cables are new, doesn't mean that they are making a good connection. Check and clean your grounds!

cubfixer · #3 01-27-2013, 10:18 AM

With the engine off, measure the voltage to the battery, It should be over 12 volts, maybe slightly over 13. Start the engine. Measure the voltage. If it is not over the voltage you read with the engine off, you have a generator or VR issue (or possibly wiring). It should be 14 volts or so. It should charge the battery until it brings the battery up to 12.5 or 13 volts. If it charges for a few minutes, then cuts out, and the battery is not fully charged, then you probably have a generator or VR problem.

fer100 · #4 01-27-2013, 10:34 AM

also clean all Ground connections Electrical and where everything is bolted at. Check the connection at safety switch. When I had my 100 this helped alot.

litlmikeyl · #5 01-27-2013, 01:37 PM

for the replies gentlemen. The tractor is sitting in the garage hooked up to the charger at moment.

fer100 - Thats a good point. When the push button switch was serviced, I noticed the screw posts were marginally pitted as was the copper bar. I was able to flip the bar over, though I could only clean the posts.