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]
 
JDS. Read your post on starter problems. Got to wondering if your starter uses a SHIM PACKAGE? if it does , the possibilities could center around the shims. Keeps the starter from fully enguaging the fly wheel. Does it (when installed on the tractor)Does it turn freely,when in the start mode? How difficult is it to manualy turn the ring gear(flywheel) when the clutch is depressed?Any Play in the flywheel,like bolts loose? You stated the starter makes A THUMP when you try and enguage it electrically,wonder if the Starter relay is so weak that UNDER LOAD against the flywheel, it hasnt the power output to enguage and turn the starter over under a load.Could it be a LOOSE connection between the ignition,amp meter,to starter?I would remove the spark plugs to eleviate the compression ratio against the starter enguagement. The reason I suggest this route is maybe the cylinders are loaded with fuel causing a higher compression in the engine and causing a drag against the starter. If that is the problem of not enough power to the starter, possible cause could be a weak starter relay. Starter would turn over with out any problem if benched checked. Another thing to check would be a GOOD GROUND to the tractor. Hope this helps. LOU.
 
You could be correct.Wrong nose cone on the starter. Didn't think of that possibility. The starter itself would turn over during the bench check, however the wrong starter (nose cone) could be the culprit. Thanks for another possibility . LOU
 
I have had this problem before on TO-20s and TO-30s. VADAVE is correct. You have the wrong nose cone. When you bolt the starter up it is locking up on the casting behind the starter. Look back in the starter hole with the starter removed. I would bet that you can see where the one you have is hitting the housing. There are a bunch of these after market starters that are incorrect. I ran into one last week on a Ford 5000.
 

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