Amel Super Maramu 2000
Could be a coincidence, but after I cleaned the exhaust elbow on the generator, I noted the voltage went up almost to 250 Volt (and actually destroyed a fan (connected to my 220 volt system). So I had to adjust the voltage on my ONAN MDKAL.
Thanks to Ben Driver (SM #347 La Bella Vita) who gave me the procedure:
Open the control box using wrenches
Remove the cover
Showing what is what
So we will want to adjust the green
Turn left / counter clock wise to reduce the voltage