This is an intermediate version of the ME1, with the inclined Mamod engine unit and stern tube and vapourising type meths burner, but without the later sight glass.
The boiler is 1 3/4" dia x 4". It has a water level plug and a combined filler / safety valve / steam dome. It is mounted in traditional manner over a typical Mamod vapourising burner. The steam pipe exits from the side of the dome and, without any superheating, directly to the engine unit.
The cylinder is a single acting oscilating cylinder type, mounted almost vertically on a cast frame. It utilises the felt pad lubrication system for the port face, fed from a hole on the top of the casting. The oil also runs down a groove in the casting to the stern tube. The engine unit is slightly inclined backwards so that the propeller shaft angles down through the base plate (and hence through the bottom of the hull when in use). The propeller shaft is inside a 1/4" diameter brass tube and has a 7/8" diameter flywheel on the cylinder end and a 1 1/8" cast alloy 2 blade propeller at the lower end.
I have not done a restoration on this engine, merely a clean up. The paintwork is in good condition and is probably original. The chrome plated boiler cowling is a little tatty but has little rust. The engine runs well and would probably power a fair sized boat.