A while back I had to move the M-16 farm truck. I hadn’t started it for about 4 months but it is usually pretty good about firing up even after sitting for extended periods. I keep a trickle charger on the battery so wasn’t worried about cranking power.
When I tried to turn over the motor nothing happened. I checked with a volt meter on the battery while attempting to crank and could see big voltage drop when the starter was trying to turn so I knew the solenoid and related wiring were OK. It appeared the starter was seized.
I pulled the starter, and happily, like almost everything else on this truck, that was easy to do. At first I couldn’t see why it wouldn’t turn but eventually noticed a small bit of metal wedged between the rotor and armature.
I had to disassemble the starter to get the metal bit out but once that was done it turned freely. I took the opportunity to clean the commutator bars and brushes. Not having a metal lathe I used my drill press and some emery cloth. It wasn’t ideal but got the job done.
I then undercut the commutator bars with and old broken pancake flipper that was about the perfect width and shape (I knew it would come in handy at some point).
The commutator was so dirty to begin with I was surprised the starter worked at all. Now it cranks over nicely but I still have to boost it with a 12 volt battery when starting it for the first time in a while (the truck has a 6 volt battery).