OK, I got my pinions and spurs in. I put the 10T pinion on with a 46T spur. Just trying it out, I programmed the MM with the lowest timing setting, the lowest start power, and 50% punch control. It was much better, but it still cogged. It cogged badly enough to strip another spur gear.

I'm finding all of this pretty disconcerting. I wonder if it is just the sheer mass of the tires. Maybe it's time to just invest in a Quark/Neu combo; or maybe a Compro/Neu combo.

The thought of a cold solder joint someplace keeps popping into my mind, but I'd think that if that was it, I'd have some other symptoms manifesting themselves. Like hot wires/connectors, or something else overheating, but all is running well as long as I'm moving, or once I get moving.