The Upshur Farm Engine Video

Please note: The .mov file is fairly large (1.33 megs) if you have a slow connection, it will take some time to load. The link to the movie follows the explanatory text.

I made this video clip with my new digital camera. Unfortunately, it doesn't have sound, so you don't get the full effect of the governing action of the hit and miss governor. As you look at the video, you may note that the exhaust valve push rod is locked in the out position (valve open) periodically as the engine runs.

When the flywheel weights spread under centrifugal force,
they pull the governor thimble out,
which latches the exhaust valve open until the engine slows enough for the return spring to push the latch away from the push rod.

 the engine then fires until the speed increases to the governed limit, at which time the valve is locked open again.

To view the movie, click here.