More tractor wiring fun

Turns out my first instinct about the key switch on the Cub Cadet 70 was exactly right, I pulled it out and found that the switch was grounding to its body.

Taking a look at the thing I noticed that the end cap where the electrical connections go was loose and tilted when they key turned. If I pushed the cap in everything was fine until I worked the key back and forth a couple times and the cap popped out again. Finally I pushed it in and peened the rim of the lock body over with a chisel, primitive but it worked.

Now the key supplies power to the coil the way it should.

While I was there I pulled the wire from the ammeter to the regulator, as I said yesterday this wire really wasn't doing anything. The last step (I hope) will be to move the grey wire from the hot side of the switch out to the ammeter. This should allow the ammeter to detect charge state while running. With luck I'll be able to use the ring terminal thats already on the grey wire without modification, as long as it will fit through the hole to the ammeter which is mounted on the right side of the steering pedestal.

Whoops

After yesterday's success I put the battery charger on the Cub Cadet overnight, today I went out to see if it would start better than in the past considering all the electricity was getting to the starter/generator. I hit the starter and it cranked over much quicker than before but after maybe half a second of cranking I was "rewarded" with smoke and burning plastic smell.

My tractor has an ammeter which has never worked. As part of the cleaning I did yesterday I cleaned the terminal where the ammeter is connected to the starter switch. It turns out that the other side of the ammeter was connected to the L terminal on the voltage regulator. This is WRONG, it should be connected to the BAT terminal on the regulator. Fortunately the wiring on the Cub is pretty heavy so all I got was a couple melty insulation spots which I fixed with tape.

I went on to make up the last heavy wire which goes from the switch to the starter/generator so now the whole path to the starter/generator is 8ga which is very heavy for a garden tractor and I'm confident that it'll never be a problem.

Unfortunately now when I turn the key switch on the voltage regulator clicks and the ignition coil loses voltage. Interestingly if I turn the switch just part way it doesn't happen and the tractor will start and run. I *think* this means that when the ammeter was wired incorrectly it forced the key switch to take full current which I *think* is allowing the switch to short out when turned all the way. I need to pull the switch and see if its something I can fix or if I need a new switch. Fortunately 2 position switches aren't terribly expensive.

The ammeter STILL doesn't work because although it doesn't cause a short anymore its still not wired right. Right now its wired from the hot side of the starter switch to the BAT terminal on the regulator but the starting switch still has a line from the hot side to the BAT terminal. To work correctly an ammeter has to be inline between the hot side of the starting switch and the BAT terminal where mine is currently parallel. The wiring on my tractor would work okay for a voltmeter except it'd drain the battery since it can't be turned off. A volt meter should really be to the switched side of the ignition switch. So to fix this I need to disconnect the original wire from the starter switch to the BAT terminal which would just leave my ammeter.

At some point I really need to re-wire the whole tractor. Another problem I worked on was that the wire from the ignition switch to the coil was cracked badly. This wire wraps around the back side of the engine and is bad on my Cub Cadet 72 as well. I used a weatherproof butt connector and a length of green wire which should have been black. If I feel real bad about it I'll blacken it with a paint pen. Of course later on I found a spot thats cracked beyond where I'd fixed. I've also got the old link to the starter/generator just hanging out. I debated cutting that wire off but left it. I'll be on the lookout for some cheap wire loom to build my new harness around at which point I'll buy the correct color wires and redo things right.

Tractor repair time

Yesterday I spent some time cleaning out the garage to fit the Honda CB900f back in. It'd been out "for sale" for over a year and sadly the shop it was at is closing down so I had to take it back. I've let the garage get very messy this summer and it really needed cleaning. That meant I had to move my 1964 Cub Cadet 70. I use the Cub Cadet mostly for plowing snow. Its got a mowing deck but it isn't as maneuverable as I'd like for our small lawn, the Snapper is a better mower really. Last winter the Cub Cadet had gotten challenging to start, often requiring a shot of ether to get going. I've got another Cub Cadet, a model 72 at camp that doesn't get used much and that ones had a fairly recent engine rebuild so my plan had been to swap them when I go north for deer hunting season in November.

Last night I got thinking that maybe the bad starting was just slow cranking. I cleaned the battery terminals and cables and the connection at the starter/generator. None of that made any difference. I measured the voltage drop at the starter/generator and found it around 4 volts! Not good, no wonder it cranked slow. I had some 8ga wire Fred had given me for the '78 240D which I'd never used and a couple crimp on ring terminals so I made up a new cable from the battery to the starter, this one was the winner, the old one was small and had a splice in it to an even smaller wire.



On the left the old wire with the splice, on the right a comparison of the new wire and the old, see how much bigger that new wire is.

I also made up a new lead from the battery to ground. Honestly I'm not sure how the old ground worked at all, it'd been attached to a painted surface. Again my new wire is much larger than the old. I also put heat shrink tubing over the new terminals. The existing terminals on the cable already had heat shrink.



With my new cables installed voltage drop at the starter/generator is now less than 1v which is entirely acceptable. I'm still going to replace the wire from the switch to the starter/generator. I would have already but I ran out of ring terminals and it was too late to go to the store. This is probably excessive but when it is done I'll know that the cables are all good and that I'm getting every bit of starting voltage I possibly can.