I have disassembled, cleaned, and lubricated the motor, gears, and E-unit, checked the brushes and polished the commutator and reassembled. I am testing the engine with the boiler still removed.  The best performance I have achieved is a halting/hesitating motion that gradual improves.  After along period of rest, the motor performance seems to regress badly and sometimes I am able to get it back to nearly normal operation, but more often it hardly improves at all At this time it almost acts as if it were stuck in idle, but the e-unit is working perfectly. It barely tries to move and then halts. The brushes are ok and the commutator was clean and bright on last viewing.  What can you tell me about such hesitating engine performance as this?
Thanks,
Mike


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