The KX21 Subaru has no different components in the bottom end than the industrial and commercial EX21 except the governor has been removed. The problem is the shaft for the governor is still intact on the KX21 engine and from what we have been able to find out the standard C Clip does the job up to the RPM range that the manufacturer recommends. We have a simple way that adds a little safety to the KX21 that requires none of the components to be removed from the engine and no additional machining. If your engine is not sealed the best way is to strip the engine and tap the governor shaft hole and put a bolt in place of the shaft.
The shaft is best removed and the hole threaded and either a bolt fitted or it can also be used as an engine breather.
The movement shown how far up the pin can move by pulling it up.
The silicone washer is placed over the top of the governor pin, it still allows for movement. The silicone washer takes some of the vibration out of the pin
With the washer in place and the governor lock collar in position this supports the clip and also if the clip comes of the collar has a better chance of stopping it dropping into the engine.