Just a bit of educated conjecture here on my part, but the humming motor is consistent with the need for a bit of lube. If it is stalling due to increased ‘drivetrain’ friction, it it very likely it will hum.
If this does not fix the problem, next port of call is power supply. If the down stream side of the supply is 12VDC (It will be written on the plug next to a flat or dashed line) I can suggest a ‘bush mechanic’ enhancement that you can try.
Bookmarks