Manufactured by W.H. Dorman & Co, Stafford, England.
The 1AB 800 cc 4-stroke single that was used in the Aveling-Barford calfdozer (a small bulldozer). There was also a twin-cylinder version, the 2AB. Production was from the mid-1940s into the 1950s.
This engine is a recent acquisition and I'm having problems with the running speed. The throttle is in the manifold with no slow running adjustment. The governor is working however the adjustment is poor. There is a second throttle on the carb, I don't know if this is original, the handbook seems to show it. i.e. was the governor stops over reving and the throttle on the carb is for the engine speed if used on a vehicle???? any comments or help with pictures of other engines would help as this seems to be a rare engine.