I have been working on a Weaver diecast 2-8-0 that runs jerky and surges. There is no binding to be found anywhere in the drive rods, or smoke piston. Turning the flywheel by hand, it feels smooth all the way. I put in a Cruise Commander and the loco jerks and surges, especially when unloaded, and particularly at low speed.
It did this even before putting the Cruise Commander in it.
My conclusion/suspicion is that the motor is bad. The motor has excessive end play and I am wondering if one of more of the commutator segments are bad or have broken windings.
It's the standard can motor that is in our China drive diesels and some of our smaller steam engines.
The only unique thing about it is the worm gear has a different pitch than all the MTH, Atlas, and Williams motors I have in my parts stash. I do not have any pitch gauges for worm gears, so cannot tell the actual pitch. Comparing it to my other motors shows that the pitch is different.
It's possible that the shaft is longer, but I cannot determine that, either.
So... where do I find a replacement motor with the correct worm gear? Can someone pull that Weaver-unique worm gear and put it on another motor for me?
This is just the kind of loco for a slow freight drag, so I want to be able to run it slowly.