jam nut

After having the desired pressure, screw the jam nut down tight on the pressure screw.

There are two little brass nuts on the top of the stem of the governor, one a thumb nut and the other a loose jam nut.

To increase the speed, loosen the jam nut and then turn the thumb nut back slowly, watching the motion of the engine all the time.

The second nut is technically known as a “jam nut,” or “lock nut.”

To set it, unscrew the jam nut and apply the key to the pressure screw.