Starting motor problems?
So.....
Long term problem - starting motors and ring gear getting into conflict on a regular basis. Every couple of months teeth go missing. New starting motors and new ring gear (one / other / both) makes no difference.
Finally, it was suggested that we check the L magneto as it might not actually retain correct advance / retard for the full time to overhaul.
Turned out to be correct. The timing did not retard correctly for the start sequence. Advanced timing was leading to the engine pushing backwards against the starter and the weakest link gives way.
In future I will be checking timing and points at the 100 hr checks. £120 for that beats the cost of a new starter and ring gear
John