I am working on a Overland,brass,HO,Rutland 4-6-0. The engine runs smooth in reverse,but the slow speed operation when running foward leaves much to be desired.It runs a little “herky-jerky” at very slow speed (almost like it’s out of quarter) but smooths out when a little more power is applied…What should I look for? Where do I start?
I’d start by breaking it in well. Run it at varying speeds in each direction for an couple of hours. Odds are high that your problem will go away.
If not, or if the engine is already well broken-in, see if it does the same thing running upside down on the bench. It almost sounds like there is a slight bearing or rod bind. If it still does it on the bench, try disconnecting the valve gear, one side at a time, and re-testing it every time.
Come to think of it, you may have a bind in the gearing - possibly needing a thrust washer in the worm gear housing…
good luck…
How old is this model? It could be the motor. A lot of the older models, even high quality ones, had non-skewed armatures and either 3 or 5 poles. They definitely tended to “cog” around at low speeds. Only cure for those is a new motor, but that probably is NOT the problem.
I am not in favor of trying to break it in when you know you have a rough spot. I would address that first.
If that motor’s not it, as noted above, run it a little upside down and then try disconnecting the motor and roll the chassis by hand and feel for rough spots. Could be a side rod or piece of valve gear rubbing somewhere.
If that’s not it, maybe the gearing match up isn’t quite right, needs a shim in or out, or even one of the ‘U’ joints is on a shaft too far or not far enough.
Just keep plugging away until you find it. After you do you will have lots of smooth running ahead.
Mike,
I doubt if it is the motor - it does not ‘cog’ in both directions. My feeling is that the worm needs a ‘thrust’ washer on one side. Or if this is a open worm on a spur gear, you will have to adjust the motor to get the worm to align with the spur gear on the driver. Take the side rods off and run the engine. If teh problem goes away, you have a side rod ‘bind’. If the problem is still there, it is the worm/gear relationship.
Jim
Thank you gentlemen…Back to the drawing board.
If your track is not clean i have found that that will cause trouble.
alexander
Get an instruction sheet from Bowser
http://www.bowser-trains.com/holocos/B-6/B-6%20Instructions.pdf
And follow thier recommendations. They are applicable to any brass or diecast chassis steam locomotive model.