1909 2-1/2 HP Dempster

From A to Z

| September 2009

  • dempster
    Gary and Dea Gruel's circa 1909 2-1/2 HP Dempster.
    Gary and Dea Gruel

  • dempster
Company: Dempster Mill Mfg. Co., Beatrice, Neb.
Year: circa 1909
Model: Class E
Horsepower: 2-1/2
Shop number: 4586
Bore: 6-1/2-inch
Stroke: 7-inch
Flywheel diameter: 26-1/2 inches
Flywheel width: 2-1/4 inches
Governing: Hit-and-miss
Ignition: Battery and low-tension coil
Additional info: Dempster engines were built with closed crankcases from early on. This was intended to protect bearings from dirt. The rod is oiled by a wick-wipe oiler, the main bearings are lubed by grease cups, and the piston and cylinder are oiled by a sight glass drip oiler. This engine is interesting as it is water cooled, with a wet head, and also has a ported exhaust system to help with cooling. It uses a fuel pump and overflow mixer with unused fuel going back to the fuel tank. All the works on this engine are on the off side. Dempster Mill is still in business in Beatrice, Neb.
Owners: Gary and Dea Gruel, 30090 West Lower River Rd., Buckeye, AZ 85326