[Humperhill]

I feel your pain. Don't give up. As you said the first two motors were unknowns so with them anything can happen at any time as you knew nothing about their history. Hopefully you can resolve your issue with the freshly rebuilt motor. As other have mentioned a well sorted motor will last quite a while and will be dependable. You will get there. Do let us know what you find out about the new motor's problem. Hope nothing serious or expensive.