Marx E-7 motor problem

Does the R-unit pull? (R-unit for Marx)

Does it pull FULLY? (Partial pull is possible on a coil)

A coil set up on ac does vibrate. How excessive that is can vary.

Are you using the same plunger? More precise, there is a pin that rides in the heart shaped opening. Is that bent? Reaches the top? 

I'm stabbing while I think

   Considering the drive works, that should be fine. One brush should go to frame via a brass strip to the brush plate's lower nut. I've never actually chased wires yet they are so bullet proof. But I have some, and should have a diagram, so I can check later too.

        There are only a couple ways to wire an open frame train motor. It is basically blind to what brand anyhow. 

   Till later, I'd  look for a short on the R-u.

  From coil to R-u frame= no continuity. 

  Then check that an R-u contact or pad isn't hitting the R-u frame somehow. 

That or wires got crossed, or are shorting on something.

Might be a wire is internally broken with only a slight connection in it as well.  Could even be a combo, but I'll bet it's the wire or R-unit contacts, not the motor.

You sir, are a genius. When you mentioned the lower brush plate needed to be connected to the ground, I remembered that the screw holding the bottom of the brush plate was missing, but didn't think it mattered as the armature still spun freely. However, that screw in fact connected the spring plate to the ground connection. Once I installed the screw I borrowed from another unit, it ran like a charm. If we ever meet in a bar, the drinks are on me.

 I didn't get a notification for your reply.... Cool, your welcome.

I was about to draw it out as I couldn't find my diagram. It must be buried in a E-cloud without preview under a crappy name, lol.

I also recalled there is an occasional EXTRA relay on some Marx. The extra relay is for engine roar sounds..... It is the sound system; making noise by fast vibration of the relay.

It's hard to fit, but weight really helps those pull more.  At harbor freight and tire stores there are flat wheel balance weights with a sticky back.  I fit a couple in place for and aft of the motor, and one or two on the mount extension. No room on the sides or rear really, that frame needs to turn. Every ounce helps though; the motors power far out does the traction.

There are also old Es and a revival done from 199Os (?). Some mechanical and replacement dress parts and body repair castings ( steps) can be had from the Robert Grossman Co  in Ohio.

Enjoy!

I've managed to fit two weights on an old style Marx E-7 motor that has the original weight bolted onto the truck frames. With a little grinding, I was able to add the newer style weight (with the points on the side) in the rear, as the motor frames are already drilled for them.  That, with the fact it has traction tires, can definitely pull.

And I deal with Robert Grossman Co. on a regular basis. He's the go to for Marx parts.

 Mine doesn't have tires.

That would be an awesome amount of traction compared to mine.