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Stuttering Bachmann
Jeremy asks:
“My new (2nd hand) Union Pacific Bachmann SD40 stutters a bit when running slow, but runs smoother when I crank up the speed. I am thinking some lube might fix the problem. Is Labelle 107 suitable, and where are the lube points? Thanks in anticipation.”
9 Responses to Stuttering Bachmann
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With out actually seeing this, I’m taking a shot in the dark here. It sounds like it might be a worn worm gear. You can take the body off and carefully watch the loco move at low speed to see if anything shows up. Also, among the list of possibilities is a dirty spot on the pickup wheels. It would be less evident at speed where the momentum of the loco carries it past the spot.
The first thing I would check is electrical contacts: clean rails, clean wheels, clean pickups from wheels/axles to motor wires. If you are really ambitious, carefully clean the motor commutator.
Ordinary 3-in-1 oil or simlar is fine for most loco bearings, you could use a light grease on worm gears.
Great points as seen above. If you decide to clean the commutator, make sure not to dismantle the motor into pieces! I learnt from the mistake of doing this. When you dismantle the motor, the magnets tend to lose the strength and after that you will have a very weak motor that will not speed up and/or will not pull the load.
It could also be that it only has a 3 pole motor which will make it uneven at slow speeds, and you might get what is called “cogging” where as the a pole of the motor comes close to a magnet it speeds up a little and then slows down, till next pole comes close to magnet. 5 or 7 pole motors does not have this problem and a skewed armature also helps prevent this. If it is a 3 pole motor you have two options, either live with eratic running at slow speed or remotor with a better motor.
I’d strip all of the old grease/oil out of and off of the trucks. Lube with Labelle 106/104
You might find that a stay alive chip will help
If there’s room to fit one.
The locomotive speed is determined by the track voltage and the design of the locomotive drive train. You may have a lower gearing engine or a poor design one. Also you might try checking your track voltage. It should be around 13.8v AC. If you have a voltage drop, then I would suggest looking at your track bus wiring. Make sure all your drops are no more than 6 ft. apart.
Check the gears and see that they are all intact. Some nylon gears have a habit of splitting at the hub area which distorts the whole assembly – momentum at speed over rides the defect.
Will check the electrical contacts gears, strip old oil etc. Great advice. Much appreciated. Jeremy.