When I went to remove the motor one of the wires would not pull out of the connector block.  I had to cut the wire.  When I could see it better the connector block was melted to the wire.  Could a loose connection here cause the switch upstream to overheat too?  The wires between the terminal block and switch are about 24” long.

When I got the end bell off, I could see that the starting contacts were burned.  Is it OK to clean the contacts up with a points file or abrasive material?  If these contacts aren’t conducting well, will it cause the switch to run hot or the terminal block to overheat?

The centrifugal throw-out mechanism that operates the starting contacts tends to hang up occasionally.  It feels a bit like residual magnetism holding it in the running position.  It only does it every now & then, and lasts about 30 seconds, maybe one-minute.  Its not dirty or sticky.  The action seems smooth.  It just seems to hang up a bit.  Any ideas on this?

DragBikeMike wrote on 03/28/20 at 22:54:12:


I think that is the culprit. It sounds like the start windings are remaining energized after the motor is up to speed, which will make the motor run very hot and eventually burn up the windings.

This from my Electrician Son

I am certainly not a cap start motor expert but I am an electrician and know how they work.

The cap shifts the phase of a start winding to give the motor direction and a rotating field to actually start moving rather than a solenoid.

If the cap is blown or not connecting via the switch then the motor would just sit there and hum[like a solenoid ;]

The switch disconnects the  cap and start winding when the motor is spinning fast enough to throw the centrifugal switch

Test the resistance of your start winding as if that is gone then the motor will need to be rewound The heat melts the insulation and that is what destroys them

You could disconnect the switch and the cap,the motor should still run if you give it a start flick Be aware it will run in either direction if you start it this way

If this test works then it is definitely your start switch or start winding
Yes you can file and clean your contacts but better to replace when you can as they may not last too long

Unfortunately I would say the start switch contacts became welded and
now cooked the start winding . If you can hand start it it should run all day and not get hot

Good luck!

DragBikeMike wrote on 03/28/20 at 22:51:48:

Best thing to do with capacitors is to replace them.
Just make sure the voltage rating is the same or  higher.

Matchless G11 wrote on 03/30/20 at 05:24:40:


All so  the value might be difficult to find, 300uF. Most caps are 330uF
I don't think that will be a problem. (May be some one with more experience with caps on motors can tell us.)  My cap replacement knowledge comes form fixing vintage shortwave/ ham receivers.  
It looks like the tolerance is 50% so might not be a problem.
But I would not go much higher then 330uF for one might have problems with current inrush.

Dragbike mike I might have a switch like that. You live near by in Jersey?