Thanks for all the observations and advice; really, really appreciate it and hope I can reciprocate . Here's where I'm at with this problem; its kind of under my skin now so I have to solve it!
Load tested the battery-It is in low end of the range on the chart that came with the tester but still within it. Note-Even though there are warning labels on the tester about how hot it gets when testing I wasn't prepared for it. They weren't kidding!
Removed Starter from tractor- counted the teeth, there are 15 as spec'd
Bench ran the Starter- Using booster cables and a short jumper for the solenoid. The gear went to the end most of the time but not always. One of the pictures shows it in motion not reaching the stopper on the shaft. I'm thinking this is the problem, at least in part. Did it about 50 times, it going to the end was random but I'd say 1 in 5 or 6 times it didn't.
It is the correct starter-Checked by Yanmar and Hitachi part numbers.
Found the old gear-I tend to toss old parts on a shelf (not sure why) Really bad wear on first 20% of gear. Looks like it wasn't going all the way up and engaging the entire tooth. Didn't notice when I changed the unit as I had in my mind it was spring tension issue.
Have attached pictures. Taking the one with starter engaged was a little weird but got it.
My thinking is there is a distortion, albeit a minor one in the shaft causing the gear not to go right to the end where the stopper is and causing limited engagment with the ring gear. When you do it by hand you don't feel it and it goes to the end.
Opinions? I think next step is to change the starter unit.
Again, appreciate the advice and interest. Am happy to be part of this group.
Load tested the battery-It is in low end of the range on the chart that came with the tester but still within it. Note-Even though there are warning labels on the tester about how hot it gets when testing I wasn't prepared for it. They weren't kidding!
Removed Starter from tractor- counted the teeth, there are 15 as spec'd
Bench ran the Starter- Using booster cables and a short jumper for the solenoid. The gear went to the end most of the time but not always. One of the pictures shows it in motion not reaching the stopper on the shaft. I'm thinking this is the problem, at least in part. Did it about 50 times, it going to the end was random but I'd say 1 in 5 or 6 times it didn't.
It is the correct starter-Checked by Yanmar and Hitachi part numbers.
Found the old gear-I tend to toss old parts on a shelf (not sure why) Really bad wear on first 20% of gear. Looks like it wasn't going all the way up and engaging the entire tooth. Didn't notice when I changed the unit as I had in my mind it was spring tension issue.
Have attached pictures. Taking the one with starter engaged was a little weird but got it.
My thinking is there is a distortion, albeit a minor one in the shaft causing the gear not to go right to the end where the stopper is and causing limited engagment with the ring gear. When you do it by hand you don't feel it and it goes to the end.
Opinions? I think next step is to change the starter unit.
Again, appreciate the advice and interest. Am happy to be part of this group.