I believe Kohler generators have hydraulic lifters.
I have owned 2 Generac’s. The only thing I can add to this excellent recommendation is to use synthetic oil. I know that I’m repeating myself!
Tom H.
... for power outages. Just plug it in you're good to go and you don't have to worry about maintenance.
PS: Seriously, that is GREAT advice.
I use synthetic oil exclusively in everything that requires oil. Dino oil is pretty much a thing of the past.
When in doubt, like cars, they actually have owners manuals
Generac Power Systems - Find My Manual, Parts List, and Product Support
The guy that installed my Generac genny does my annual maintenance. He has never to my knowledge adjusted the valves. The unit is 17 years old. I just checked the manual and that is not listed in the service requirements.