931B starting problems

When it rains, it pours!!! I had the battery checked in my 931B and it was putting out 1200 cranking amps, so I ruled it out as the problem. In the past when I thought the battery was low, I was always able to boost it. I cleaned the battery connections and am getting 12.58 volts at the starter solenoid, the same as the battery volts. I get a light click and sometimes I get a louder click but never got the engine to turn over. It has a Nippon Denso starter that I had checked out when the engine was out a few years ago.

There is a small solenoid that feeds to a larger solenoid. The small solenoid is what makes the lighter click sound. If I put a jumper wire from the small to the large solenoid, it does the same thing as turning the key. The only light I have is a little light for the dash. It dims when I get the click. I'm wondering if maybe the large solenoid is stuck or has carbon deposits on the contacts like my skid steer with a ND starter had? I've also read bad battery cables could show good voltage but fail with a starting load? Is there a way to take the solenoid off without removing the starter or could it be something else? Attempting to remove the starter would be the worst nightmare in the history of man. I can probably lift the boom up with skid steer to have a little better access because it's hard to see with the lift cylinder in the way. Any help is greatly appreciated.

Sounds to me like you've probably got the problem figured out, a bad solenoid on the starter. Like you said, the lighter click is the small solenoid, and the other click sounds like the solenoid on the starter pulling in. The problem is it's not making contact internally due to corrosion, burned spots on the plates, etc, to put voltage to the starter motor.

As far as the repair, unfortunately, most of the equipment starters I've seen need to be off the machine to change the solenoid. That said, it might be the solenoid is working, and passing current through it, but the starter motor itself is bad. You can check that by jumping the two posts on the back of the solenoid and seeing if the starter runs. It won't engage the bendix to turn the engine, but it will tell you that the starter motor itself isn't the problem.

Now, given the difficulty of working on it with the arms down, you can do as you suggest and lift the arms with another machine and block them. Or you can try this trick if you know the starter motor will run. First hook up a remote starter switch from the big hot leg on the starter solenoid to the smaller start post on the solenoid. This way you can stand close and feed power directly to the solenoid to cause it to pull in. This will engage the bendix teeth into the flywheel ring. At the same time take a pair of jumper cables and hook one leg to the big, hot leg on the solenoid (or another high amp connection), and the other leg on the same end to the other big leg on the solenoid on the side that goes into the starter.

The next part will be easier with two people, but I have done it alone, so it can be done. Now with the remote start button hooked up, and the jumper cables hooked up, you now have the ability to remotely power the solenoid and engage the bendix, as well as using the jumper cables to jump the internal switch in the solenoid and supply power to the starter motor. With the bendix engaged, and power to the motor, it should turn the engine over.

Now push the remote start swith, and get the bendix engaged, and at the same time touch the other two ends of the jumper cables together to cause the motor to turn. As soon as you hear the engine start let go of both connections so the starter will disengage, and quit spinning, just like it would if you were using the key.

Like I said, it's easier with two people, but it can be done alone if need be. It's not pretty, but when faced with the alternative of the work required to lift and block the arm with another machine, or try to work on the machine in an impossible configuration (ie arms down) it's worth the trouble to try. Worst case your back to getting another machine to lift the arms, best case you get the machine started, and the arms up and blocked, under the machine's own power, to make getting the starter off so much easier.

Good luck.