Designation Boiler feed pump
Bore 1/2  inch
Stroke 3/4 inch
Configuration Steam pump
Extra equipment Drain cocks
Displacement lubricator
Taps required 5, 7, 8 BA
5/32, 3/16 x 40 tpi
5/16, 7/16 x 26 tpi
Notes An interesting engine, direct-coupled to a boiler feed pump. It's basically a conventional slide valve cylinder block, with the piston rod connected direct to the pump piston. The valve rod is shuttled back and forth by the gunmetal Y-piece on the piston rod, reversing the direction of the piston as it goes. they pump well from 10 strokes a minute upwards, Stuart recommend a maximum rate of 200 strokes per minute.

This engine needs good workmanship to get it to work well - the "flywheel-less" configuration is not forgiving of tight glands or out of line spindles. About half the ones I get in will never work, half of the remaining run but don't pump effectively, the remaining few actually work nicely!

These pumps do need a displacement lubricator if used for boiler feed work.