Strange ignition system. Only ignites when the RPMs drop. I'd guess it's a pretty heavy flywheel to crank over?
What would this have been used for? Driving a pump?
This is a "hitt & miss" engine which which refers to the ignition system it employs which was a common design for that engines of that era. One of the flywheels would have a governor system built in such as a weight that would move outward when the flywheel was rotating at higher RPMs after the engine fired. The movement of the weight would disengage the ignition system until the flywheel slowed down enough for the weight to move back into place and re-engage the ignition system for it to fire again. There is no spark plug in this engine either. It has a magneto connected to an ignitor located at the head of the cylinder. The ignitor has points that remain closed until opened mechanically by the ignition system when time to fire. The open points then have the current running through them making the spark to fire the engine. The mechanics of the ignitor I tried to show in the second video I posted on youtube.
http://www.youtube.com/watch?v=DfeNP4-olM4
The flywheel is pretty heavy too, but effort is relieved somewhat by a compression release valve that reduces the compression and advances the spark to help get the engine started. The lever I move after getting the engine started in the video is disengaging the spark advance/compression relief.
Engines from this period were made in all sizes and would have been used for any job that electric motors were used for later. Small engines ran small equipment such as washing machines and larger engines such as this would have run saws, mixers, pumps and any other misc farm machinery of the time.
More info than you probably wanted to know, but hey, if I can talk about AV equipment AND old engines & tractors here... I might not ever leave!
-Brad