My engine suffered terribly trying to run when I got it. It did some of the things your engine does. Mine didn't stutter as much. It seemed to bind and then would take off at higher speeds until the red TMCC knob was turned down enough to slow it down. Then it would seem to almost stall and do it all over. The loud buzzing noise at every start and slow down drove me nuts!
I tore the stock board set out of my Sunset Allegheny and installed PS2. The engine ran so much better. The PS2 board looks at what the motor is doing and adjusts from that. I think the early TMCC style board set that came in the engine didn't care what the motor or the engine was doing.
I don't think your engine needs any shimming!
"an older 3rd Rail Allegheny with MTH's PS2 control boards and smoke and now the motor control is much smoother. It smokes like a champ in time with the drivers now too. I need to get the right smoke unit for it with the double stack funnel. I'm happy now with the performance of the engine."
I wonder if you could change the settings of the board using the cab 1 so that it ran smoother? starting voltage, etc., like the DCC guys do.
