Can a stuck key fry a solenoid? (2072)
 

I was starting my 2072 in very cold weather the other morning. It normally starts fine, but it was very hard to start in near 0 temps. It finally fired and I removed my hand from the key to adjust the throttle. I drove it around the farm for about 20 minutes and when I shut it down, I noticed the key switch had been stuck in the start position the whole time. The internal spring had broken and corrosion inside had apparently caused it to stick.

When I tried to start it again, no electrical power. No oil light, no headlights, nothing. I happened to have a screwdriver in my pocket, so I jumped the two big terminals on the back of the solenoid and it started right up.

Took it back to the barn and went to get a new key switch. Replaced it and the fuse which had blown. Now I have lights, but it still won't start with the key switch. I jumped the terminals a second time and it started, but blew the fuse again. Does this mean I have a bad solenoid? I don't want to buy a new one if I don't have to. Thanks - Chris

Here is a simplified schematic for the Start Circuit for the 2072.

Here is some testing to do with a DVM or VOM.

With the meter set on a Resistance Scale (ie: Rx1, Rx10, etc) place the black meter lead on the Black Negative Battery Terminal.

Do all you test points with the Red Meter lead.

Start with taking the Small Red Wire off the Starter Solenoid. With this wiring hanging in mid air, you should have NO resistance readings no matter what, when the Key Switch, PTO Switch, or Brake Switch is engaged. IF you do, then start isolating until you find the short.

Next, testing the solenoid itself. I do not know the exact specification on the solenoid coil, only an educated guess. IF you have from the small terminal to ground, say 200 to 2000 ohms, the solenoid coil is probably OK. If it is over 2000 ohms, I would venture to say, the coil is toast. IF you have under 100 ohms....then this coil is shorted.

Do the testing and let is know.

http://i176.photobucket.com/albums/w...9.png~original

A little late, but just wanted to say that I finally got this sorted out.

I went through the wiring using R Bedell's diagram and tested everything. Everything seemed to be okay. I googled the numbers on the solenoid and the specs said this one was rated at a max of 10 seconds for each start attempt. I guess 20 minutes of power through the solenoid was a little too much. Put a new solenoid on and it started right up.

Glad you got it isolated and fixed. I have a 2072 too, well sort of anyway. Mine was reengined with a Kohler Command 18 hp so the wiring is different than yours. I have read that the 2072 is a bit notorius for hard starting in cold weather. I suspect the battery position at the rear may be a contributing factor to this. I replaced my cables with a lot of overkill #2 copper cable that my son can get at his work. We have it apart at the moment so haven't tried to start it lately to see if that huge cable helps with cold starting or not. We have been having all the cold weather lately just not the opportunity to test anything engine related.

Great news! :beerchug:

Glad to hear!:beerchug: