cranky old loco

I'm looking for tips getting a 20-year old Mantua HO steam loco to run better. It goes ok at medium to high speed, but at low speed it's
jerky and prone to stopping.
I've taken it apart and worked it over. The chassis rolls easily enough. Motor is not in a can but seems to rotate ok at low speeds. It just doesn't seem to have quite enough oomph to keep the tie rods moving steadily, especially when it's pulling any weight.
Is there any hope for it?
-- Jim
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snipped-for-privacy@jimdill.net wrote:

That means both (mildly) tight spots on the mehc, and poor current collection. Put a small drop of contact cleaner/lube on all pickups, and a very small drop on the commutator. That will help, but will not be a 100% cure.

Yes, there's hope. (I assume you've eliminated binds, as you say the mech rolls freely without the motor.) These old Mantuas need breaking in. Run it dry at medium speed for about 1/2 an hour in each direction, then lube it. Use a light oil for the motor bearings and wheel bearings. A very light oil for the crank-pins. Grease for the worm and gear. I squirt a dab of Teflon powder onto the gear, too. Small drops only! Use a pin or toothpick to transfer lube, or an oiler with a fine hypodermic tip. You should see smoother and hear quieter running at all speeds. In fact, the more you run it, the better it will run. Labelle and AeroCar make lubes suitable for models.
OTOH, it's possible that the magnet may have lost some strength. Weak magnets lead to high current consumption, so check that. It should be at most 1 amp stalled, and at most 1/2 amp hauling a near-wheel-slip load. If the magnet has weakened, the replacing the motor is about your only option. Remagnetising DC motors used to be a pretty routine procedure, but I wouldn't know where you could that done these days.
HTH
--
wolf k.

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Jim,
There is a Yahoo email group called yardbirds. Those guys are all really interested in theolder locomotives and I'm sure that if you joined their group, they would be happy to supply you with tons of advice on everyting to check on to get better performance. I scan the posts and pick up some really good stuff from time to time. And the group is pretty friendly.
Check them out...
dlm
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Thanks guys, much appreciated. Sounds like time for a trip to the oil store.
-- Jim
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On Thu, 3 Apr 2008 17:03:25 -0400, "Dan Merkel"

They have their own web site with parts for sale, also. www.yardbirdtrains.com
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What do you mean by "rolls easily enough"? You need to be able to remove the boiler, motor, and worm, and then give the chassis a push down the track, and it should coast for a couple feet with the drivers and rods rotating without catching and stalling. If the chassis is any less free than that then you still have binds that you need to resolve. Geezer
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