736 Runs Hot

As long as the mechanical transmission is loose and free-wheeling, it sounds like the lacquer on the motor windings is breaking down. This causes shorts in the wire and more electricity flows on a shorter wire path, causing heat.   There have been many threads about this issue, and how to correct it.  Usually it means a rewind of the motor armature.  There are probably guys on the forums that offer this service.

You might want to review this page:

http://themotordoctor.com/armature_rewinding.htm

The motor doctor rewinds arms but he ain't cheap. Make sure there is no gear binding. You may need motor/chassis shims.

Rob

Although you didn't say anything about it, I assume you lubed the driven gear, checked to make sure the armature had a bit of end play inside the motor housing, and that the mechanism is not dragging or binding. If you have a friend that has an MTH Z4000 transformer, try your loco on his layout, and see what amperage draw you are getting. At 12 volts it shouldn't draw more than 3 to 3.5 amps, less if the smoke unit would be unhooked. Like the motor doctor page shows, the windings might be losing the insulation on the wire wound around the armature.

Hello guys and gals.........

probably best thing to do is to replace the motor from parts suppler such as from Jeff, the train tender.

the woman who loves toy trains

Tiffany

before you pitch or rewind the armature try soaking it in clear laquer first. A couple of dips with 3 -4 minutes between should do it. Clean with  thinner the communtator and sides. Let dry for 24 hours and try it, if the short isn't too bad this should work. good luck

Regards,

joe geiser

I had a 736 that did this too and I found the rollers on the pickup were the culprit. I removed and replaced them with new ones and the heat disappeared, not saying thats your problem, but check them to be free rolling with no binding.

Good luck.

Rod

There's other things that could be the issue. First get the wheels in the air and run the engine with a separate ground wire to the motor to see if the chassis has a ground issue. If that doesn't help, take the motor out and run it separately. Keep the temporary ground wire connected to the motor frame for this. If it doesn't over heat the problem is else where. If it still gets hot then disconnect it from the eunit and run it straight off a transformer. You will need a couple more jumper wires for this. If the motor still gets hot then at least you are sure its the motor. One example of where there could be a problem - If the side of the eunit drum is touching the side wall of the eunit you can have this sort of motor problem. On Eunit drums that were poorly made or became over heated themselves the plastic can let the metal end of the drum move off to the side making the drum wider and causing an almost imperceptable short against the inner surface of the eunit side wall.  

I'd like to thank everyone for their help and suggestions.  I took the motor apart again and rebuilt it using anothter winding and it seams to run much better, it still getss worm but nothing like before, so far it looks like it may have been the laquer on the windings. Next I plan on replacing the e-unit drum and rollers as suggested.