Mr. Heater Gas Valve Problem

They are generic unless the mounting is enough different that you just can't get it mounted and in that little heater there might not be much fiddle room. Without looking at it hard to say. I used to carry a couple different ones on the truck, and don't remember being "stuck" for lack of. But since you don't have any I'd be tempted to try to find an exact replacement. I don't think, overall, there are many different ones

The power / voltage is supposed to be the same. As long as they are a 750 mv thermopile, "in theory" they should work electrically