Huskee electrical issue in ignition circuit
I have a Huskee lawn tractor/mower purchased new from TSC back in 2002. It's a hydrostatic drive with a 50" mower deck with a 23hp Briggs V-Twin. The MTD model number is 14AR807P131, S/N 1B051H10595. It's been a heck of a mower until last weekend. I had been mowing for several hours and needed to stop for refueling. After topping off the tank, the ignition key failed to get even a click from the solenoid or any sound from the starter. I had inherited this mower from my father, but did not get any kind of manual with it. Being a reasonable shade-tree mechanic, I started looking around for obvious problems. Battery is new with good connections. Poking around under the hood, while tracing wires, I discovered the fuse holder behind the instrument panel that serves the ignition circuit. The 20 amp fuse was blown. Before trying a new fuse, I examined most of the wiring harness to look for chafed or broken wires, or a loose ground connection somewhere. Everything seemed to be in good order. I removed the fuel tank to further examine the wiring behind the dash. I checked and cleaned all connections to the ignition switch, electric PTO (blade) switch, but still could not find anything amiss. I reassembled everything, reconnected the battery, and replaced the blown fuse with a new 20 amp. Settling into the seat, checking that the PTO was off, and stepping on the brake, I engaged the starter. Bingo, it took right off and ran perfect. I was uneasy about the blown fuse, however, and shut the ignition off to take one more look under the hood. Everything appeared OK, no smoke or burnt wiring smell. I tried starting it again, and nothing... I looked at the fuse holder, and the new fuse had blown. I fetched another new 20 amp fuse, but upon trying to install it, it blew the moment I plugged it into the fuse holder. One subsequent attempt produced the same result. I am baffled about why I was able to replace the original fuse without incident, and start the tractor normally. Now, I'm unable to introduce a new fuse to the holder without it blowing as soon as I touch it to the fuseholder contacts. Reviewing all of the wiring again reveals nothing obviously wrong. I don't want to start replacing safety switches, ignition switches, and solenoids without bouncing this problem off of some of the sage diagnosticians here who might be able to describe a methodical approach to isolating this electrical gremlin. I have downloaded the proper owners manual from MTD's web site. It has been helpful in all ways but one. It contains no wiring diagram. I scrounged around on the web and downloaded a Huskee tractor wiring diagram that appears to be close, but isn't an exact match. The way I understand MTD's policy, is that you have to buy a Technical Service Manual if you want a wiring diagram. I'm not ready to do that yet, but may be forced into it at some point. Any help would be very much appreciated.