Starter Issues

[AllanD]

I've had my Super A for half a dozen years or so and have had the same intermittent problems with the starter. It has happened probably 3 other times before today. At random times the starter won't turn over, just dead. In the past I removed the starter and put it in the vise on the bench and hooked up jumper cables to a battery and it spins right up. I replace it on the tractor and all works fine again. Since it worked fine I never delved any further into it.

Today after several hours of grading the drive I stalled it and when I tried starting again the same old issue reappeared. I towed it back to the shop, removed the starter, hooked up the jumper cables, pushed the switch lever and it spun right up in the vise as usual. But this time when I reinstalled it, it is still dead. No spin, no click, no movement all. Here are some facts:

Battery relatively new and measures 13 V at terminals.
I'm getting battery voltage at the red cable on the starter to ground.
All battery terminals, and positive cable on starter are clean.
I get continuity from negative battery post to mount on starter.

Any ideas on why the starter works on the bench but not on the tractor? Thanks!

[Don McCombs]

Given the results of your testing, my initial thought would be poor ground between the starter and tractor chassis. Take the starter back off, clean up the mating surfaces and all connections and then retry. If this doesn't produce positive results, I'd look at the condition of the starter switch.


Photo courtesy TM Tractor Parts

[BullDAWG]

+1 on clean ground (where starter mounts and the starter itself) if any paint, oil etc is there it may not be grounded. Also check the starter switch, make sure it is mounted well to the starter and that the switch is working properly. When on the bench you may be pushing it enough to make good contact but while on the tractor the rod you pull might not be moving the arm and making good contact. Check for good movement and that all the rod movement along with the arm mounted to the switch have free movement and are working properly. I had issues with this as the starter switch wasn't tight and between it rotating a little and the arm being loose when I pulled on the rod it wasn't making the switch properly make contact between the hot wire and the starter so it wouldn't turn over.

[AllanD]

Thanks guys. It was a good idea to clean the attachment to the block. I removed it again and cleaned with a old dull file and 120 grit sandpaper. When I reinstalled the starter it spun right up. Good news! Now the bad news. The engine didn't catch on the first crank so I cranked again and now it was dead as a doornail again. I removed the starter and spun by hand, reinstalled, but still nothing. So this afternoon I ordered new brushes and a new switch for it. I agree with both of you that there is mis-connection electrically somewhere. I will keep you updated.

[BohemianJon]

If all the connections are good, might be time to rehab that starter...I had similar problems and as long as I had it off took it in and had it tested...re-built and all has been good since.

[AllanD]

I thought I should follow up with this thread. I took the starter apart and found that the brushes were slap wore out. The commutator was actually grinding off part of the screw heads holding the brushes. I ordered a new set and a new starter switch and just now put it back on the tractor and it starts twice as fast it seems. While I had it apart I shined up the commutator, filed all the screw connections inside down to shiny meta, and lubed it.

Now the rest of the story is I just saw the two spacer washers still on my bench so tomorrow I will take it off and apart again and try not to leave anything out this time! Thanks for everyone's help.