TO-20 new starter won't turn flywheel

jd's

Member
Hi again,
First I want to say I am very sorry for not responding to the post I made to this forum on 06/23/10, titled "TO-20 won't make a sound".
My computer, like my tractor, decided that it wasn't going to start for me either! Now that it's up and running again, I was wondering if I could possibly pick your brains again?
I truly thank all five of you who responded to my post, and hope I have not lost your trust.
I own a 1951 TO-20 that was converted to a 12 volt system about a year and a half ago. The local tractor mechanic gave it a complete going over and it ran like a top.......for about one week. It wouldn't start, so he came out and found out the starter had finally failed. He replaced it with a brand new one, and it ran perfect for about six months.The tractor always started with just the slightest touch of the shifter to the start position. Without any warning, upon trying to start it one morning, it made a loud grinding noise followed by the sound of rattling metal, and a parting small mushroom cloud of smoke from the starter. I removed the starter to find the pinion and the nose housing in pieces.
This brings me up to a couple of weeks ago when I posted here for the first time.
I bought another starter and tried it, but it didn't make a sound. Checked the battery, the cables, and all the wiring and they were fine, with the battery showing about 13 volts on the meter. I thought that it may be the STARTER SWITCH, (on the housing below the battery) and replaced it. That didn't work either so I posted to you.
I was wrong in my first post, by calling the STARTER SWITCH a solenoid, and do apologize for all the confusion I caused. I'm still learning.
I tried the suggestions in your replies to me, and decided to bypass the wiring by jumping the starter on the tractor; still not a sound. Next I tried jumping it with my truck hooked up to it. Still nothing. I removed the starter for a bench test and it ran at full speed out of the tractor with the tractor battery. I put the starter back in the tractor and tried it again, and it made a thumping sound, then nothing. It didn't spin or make a noise. Took it off again thinking that if I moved the pinion back to the fully retracted position on the bendix, that might work. It didn't. It thumped again then didn't even make a spinning or turning noise.
I decided it was time to report back to you, and found my computer fried!
Next I called the tractor mechanic, and although he was busy on lots of other tractors, said bring in the starter and bench test it. It ran fine for him with a worn down battery off an old tractor. He even stuck a screw driver under the pinion to give it a load to fight, and it almost shot the screw driver out of his hands. Even though he felt that there was nothing wrong with the starter, he got me another brand new starter in the box, to take home and try. So I went home and tried again, doing everything that I had done with the first starter, with the same results...... nothing but a thump mounted to the tractor. Took it off the tractor and it ran just fine on the bench with the battery.
Once again I rotated the flywheel around checking every tooth on the gear. There is just a slight bit of wear on the outer edges of the teeth, but that's it. As I was reading thru many posts I saw one that said he measures from the mounting face of the starter and the tractor to determine if the pinion is far enough out of the way of the flywheel when retracted, and to check the full forward position of the pinion where it should engage the flywheel gear. I measured and found that the pinion clears the flywheel by almost an inch retracted but only engages the flywheel gear by about 5mm in the forward position. In the post it said that there should be full engagement on the flywheel gear and I'm only getting 5mm on a 10mm wide gear. Could this be a problem?
There would be no other way to get the pinion to engage any further unless I grind down the mounting surface of the starter to get the pinion more engagement.
Of course I don't want to attempt that radical of a move on a new starter but I'm quickly running out of ideas. HELP!!
There are no model or part numbers on the starter so I can't compare, and I don't have the first starter that broke, because I returned it to get the new starters.
Once again, if anyone has any ideas at all that I could try, I'd be forever in your debt! I really think I'm going crazy!
THANKS AGAIN!!!!! Jack[/b]
 
Have you checked the ground cable connection? That is half of the current path to the starter, and it can go bad just like a bad cable on the 'hot' side.
A quick check would be connecting a jumper cable from the battery ground terminal to the starter frame and trying again.
 
It's not unusual for the bendix to only partialy engage the ring gear. But you may double check the bendix to be sure it is the right one--a lot of starters are the same but the drives are different for different tractors.
 
first, clean off the tractor frame where the starter mounts, sounds like a bad electric connection when you bolt it on. 2nd, I have broken off several nosings. The fix is make sure the starter has a new bronze bushing and new brass thrust washer. Also look at the flywheel teeth and see if any are mashed flat. If so, use a small triangular file to re-shape the tooth. The bendix teeth need to slide between the flywheel teeth, not hit straight on. If they hit straight on, broken nose. Lastly, try a smaller guage battery cable to the starter to slow it down.
 

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