If you have a "knub" cyclinder on the top of your gen. It's a cutout (as murre said) not a regulator. Off/on.
https://www.amazon.com/AQP-Tractor-G.../dp/B0714F7K44
https://www.completetractor.com/new-...9n-b0nn10505a/
ford38v8 link is good too.
A diode is used to limit current flow in one direction.
Main
functions. The most common
function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking it in the opposite direction (the reverse direction). As such, the diode can be viewed as an electronic version of a check valve.
.