The point of hit and miss engines is not that they disable the spark above 
govern speed, though some do. It is that they leave the exhaust valve open - 
hence the wheezing noise!  Thius means that they dont need a throttle, which 
is for various reasons a waste ofd energy, and the combustion conditions are 
always the same. This removes one dimension from the problem of tuning which 
makes the engine able to work on a variety of fuels, and get good efficiency 
when running light.
The throttled stationary engines became important when used for electricity 
generation, where for AC power you dont want bangs every secondor two or 
three...!
 
--- Maximus 2.02
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