I cannot find a wiring diagram for this unit so the below is a bit of guessing.

Try rotating the drum, just in case it is binding etc. and putting too much load on the motor. It should rotate fairly easily. You may want to try this on a couple other units just to get a feel for it.

If OK
Check the power to the unit both L1 to Neutral and L2 to Neutral should be 120 volts.

If OK
Check for any sign of overheating/corrosion/loose connection at the terminal strip.

If OK
Check that you have the correct power at the terminal strip.

If OK
The motor circuit usually goes through one set of contacts on the timer.
Check the motor side of the contact set when starting the unit to see if the motor is getting 120 volts.
If not
Check the power side of that contact set.
If it has the full 120 then my guess would be that the timer contacts are badly pitted and they are dropping voltage so the motor is not getting the correct voltage. This can be double checked by measuring voltage across the contact set. It should be 0 volts.

This could also happen with the start switch.

[COLOR="Red"]Be very careful as there is 240 volts at the timer etc. and this is lethal!!![/COLOR]

You may actually be able to check the contacts using ohms with the unit unplugged. They should be 0 ohms when closed. I would try this first.
If they are 0 then you will have to do the power test as the ohms test is not totally reliable.


You have a weird problem so it will probably be a pain to troubleshoot.