Mantua loco - needs new motor?

Poor running and pulsations on a steam locomotive are often a sign of binds in the side rods and/or valve gear, particularly if the slowing down part of the pulsation always occurs when the drive wheels are in the same rotational position. Take off the boiler (one screw at the front in line with the stack, and two at the rear under the cab), and take off the motor. Make sure the mechanism is properly lubricated. Roll the mechanism on the track. The wheels should rotate smoothly under just the weight of the chassis. If the wheels lock up, it means you have a bind. One at a time take off the valve gear first, then the main rods and last the side rods, and after removing each item, check for smooth rolling - when the bind goes away, you know where the problem was. If you don't have any binds and the mechanism rolls smoothly (you should be able to push it down the track and have it coast at least a couple feet), then you may have a bad motor. GQ

Another possible problem may be with the tender trucks electrical pickup, I've had a problem similar to yours and replacing the tender trucks with MDC trucks cured the problem. Try running the Loco on the bench to check for side rod binding as an earlier reply by Geezer stated. Also check the connecting wire from the Tender sometimes cleaning this area will work.

Changing the tender trucks may require some filing and tapping of the area around the screw holes.

Good Luck

You may also want to check the feeders inside the loco, probably they or the metal wheels became oxidized and need some cleaning.

You wrote on 11 Dec 2003 11:16:15 -0800:

T> I have a Mantua 2-8-2 that is about 12 years old, but has probably T> fewer than 3 hours on it since its spent most of its life in storage. T> It has never really run too well, and at this point I constantly have T> to tap it to get it to go. It is almost impossible to keep it at a T> realistic, scale speed, since it will stall. Also, it seems to T> pulsate a little while moving along, as if it is not getting an even T> flow of power. I have numerous power feeds around the layout, and I T> have not noticed this problem with my Atlas and Proto2K locos.

T> Any suggestions? Do you think I need to replace the motor?

With best regards, Sun Cheek. E-mail: snipped-for-privacy@No.spam.suncheek.tk

And, if you cannot find a bind in the rods and valve gear, check the worm gear. Sometimes they were bored off center, or have a munged tooth somewhere. Mantua made two can motor conversion kits Part Number 811 and 812. The 812 fits the Pacific. I did some timing trials, before and after on my Pacific. Before (standard open frame motor) gave a slowest scale speed of a few scale mph, quite respectable for a steamer even today. The can motor conversion dropped that down to a phenomenally good fraction of a scale mph. However, the stock open frame motor gives very good performance, nearly as good as the Bachmann Consolidation. The Mantua assembly instructions for the 2-8-2 Mikado read like this "7. Check rotation of the coupled drivers. Tight spots on the side rods may be freed by reaming slightly with a round needle file. DO NOT REAM any more than is absolutely necessary. Assembled mechanism should roll freely." "15. Lubricate worm and gear with Lubriplate or any good light grease. Apply a drop of light oil to all other moving parts. Turn mechanism upside down and in this position run in mechanism for not less than 30 minutes with 12 volts, DC power. Reverse direction of rotation one-half the run in period."

The Mantua locos really don't go very slow so that may be one of your problems. A regear would be what would be needed there to get slow speeds (under about 30smph). In addition, you will want to lubricate the loco, clean the wheels and the tender bolsters to insure good contacts for the current carrying. I usually put a wire to the trucks directly and also put contact shoes on my locos to improve the electrical pickup of the loco.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works evevery time it is tried!