Hey Tom,
I refrained from posting because I haven't replaced the starter drive on the MZ-4162.
However, I have replaced the Bendix on 2- MZ-4113 starters and I have repaired the MDU-7004 starter drive that comes on a CJ5 starter.� The repair to the MDU-7004 was a nightmare.� There were hidden lock rings that were difficult to get to.� I really needed� 3 hands.�
Replacing the Bendix on the two MZ-4113 starters was a piece of cake.� The hardest part was trying to hold back the motor brushes while sliding the motor assembly back into the housing.� Again, 3 hands would make it a snap.
If the starter drive engages 7 out of 8 times, then it's probably okay.� A screech sound is new to me.� Perhaps the starter just needs to be cleaned and lubricated.� A screech sounds may be a lack of lubrication, but I think you would hear it during every start.�
Maybe one or more of the brushes are worn enough that the brush holder is making contact with the motor communicator.� But again, I think the screech would be heard more consistently. �
Perhaps there is some foreign debris in the housing that occasionally gets caught between the housing and the internal spinning parts.
I think if it were me, I would carefully take the starter apart and inspect it.� �While open, clean and lube it. You may be surprised how dirty they get inside.
My MZ-4113 starters are 6 volts.� Both are on Willys Jeeps that have been converted to 12v.� They perform fine.� While starting, you just don't want to engage them for long periods of time.� If mine doesn't start withing the first few seconds, I stop, then start the process again.�
Oh, I would add...If your starter reallys spins quickly...like a bat outa hell, then it may still be 6v. If it spins a little slowly, like the battery is in need of replacement, it may have been converted to 12v.
Tim