Marx's other tin F-unit

Well, got the motor back together and it's running, but the big orange loco can barely move the B unit and caboose! It just sits there with the wheels spinning. Maybe I got too much oil? Maybe it's missing a weight? Anybody else have one of these beasts?

Thanks!

I've seen a few of these in the wild and have picked them up but never run them. It would seem to me the same thing applies as with all marx units. clean commutator, clean and greased gears and loob... Maybe the armature isn't wound for for the gearing... or it's flat out missing a loop. Was it hard starting on it's own? How long have you test run it on its own before putting them together? You can try sticking a roll of nickels in it and see if that helps?

It shouldn't need any weight to pull a dummy and 3-4 seven inch cars and a caboose. Do the normal cleaning of the drivers as you already stated, but I'd look into the center pick up having too much tension and keeping the drivers from making good contact as well as the wheel gauging being a bit to wide.

Steve

Thanks guys! I'll keep working at it.

The motor would not even turn once before the surgery. Now it is beginning to run a lot more smoothly. Think i may need to replace the brush plate too as the armature seems a bit wobbly in it.

Cleaning track and wheels has helped. I will check the gauge next. I may not have gotten the wheel I removed back on properly.

Mke sure the wheel is not on to tight nor to loose to engage the gears.

Going back to the old motor dont give up just yet, you can try soaking the brass bearing and end gear only in shallow cap such as one from top of a paint can in lubricating oil to see if it will help loosen it more since you can turn it somewhat with pliers.

Also that bearing has a groove that matches and fits into a notch in the motor frame upon reassembling.

The bearing this way does not spin but the armature shaft spins in the brass bearing but you probably know that already but may help others looking at this thread.

The motor is running fine now with the replacement armature and brush plate from the donor motor. I will try soaking the original armature bearing in oil to see if it will eventually loosen up. Then I'll have another spare.

I moved the wheels in just a smidge so that there is a little play in the gauge on curves, and after another cleaning of wheels and track, most of the traction issues are gone. Still having a problem on curves and on a couple of straight pieces of track where the loco loses traction. At one point it looked like the piece of tin the front grooves of the motor ride on was holding the front axle off the track a bit, so I tweaked the bracket a bit. That helped some, but not completely. The loco is able to start the train (dummy, 2 - 7" cars, and caboose) and keep it moving at a good clip with just a bit of wheel spin on curves and the one straight section. There seems to be a lot of binding so the rear (powered) truck has trouble swiveling. It was like that before I adjusted the bracket the grooves slide on. I even put some oil on the top of the motor mount where it rubs against the big washer under the roof. It looks like the round portion of the motor mount isn't parallel with the motor. Like the 90 degree bend at the top is just a degree or two past 90. Could that be part of the problem?

After some more tweaking of the brackets, I followed Steve's lead and checked the pickup shoe. It looked a little misshapen so I tweaked it a bit too.  LOL

After all that she pulls pretty well now. Not only will she move the dummy and caboose, but also a six car train of mixed 6" and 7" cars.

Also tried something new to clean the old girl up. Toothpaste. I used one of the little samples the dentist hands out after each checkup. Nice mild abrasive that really polished the old girl up.

Thanks for all the responses and suggestions everyone!

toothpaste...have to give that a try.

handyandy posted:

... Also tried something new to clean the old girl up. Toothpaste.  ...

toothpaste is a very mild abrasive.
i've used it before to polish hazy eyeglass lenses.

Is there supposed to be a lock washer on top of the large washer that sits on top of the motor mount? The one I purchased came that way but it looks like the tin body was up too high so I removed it. Now it seems a little too stiff to swivel easily.

No lock washer anywhere. It needs to be loose. The round mounting plate, then the large round washer. From the top, the mounting screw that needs to have a shoulder.

Steve

Thanks Steve...have the large washer and the mounting screw, but someone had placed a lock washer on top of the large washer so I wasn't sure if it was supposed to be there or on top. Many thanks for advising me it is not used at all.

The motor or the whole loco could have been dropped at some point, and the motor side plates shifted, to the point where they are no longer parallel and all four wheels aren't making good contact with the rail.   This will definitely lead to wheel spin at all speeds.  It could also help explain a seized bearing or excess friction in the gear train.  Unfortunately, if the motor is "staked" together, I'm not sure how you would solve the problem.  If you try to rap it back into alignment, you might loosen things up further :-(

I will check on that, thanks.