Thor Forums

[Beau388]

Contamination is the reason for an oil change, as oil does not wear out. Contamination can come from cylinder blow-by or water from condensation.
Cummins Onan recommends running the generator for at least one hour, under load, each month. This is to put new fuel in the carb to avoid the carb gumming up as the gasoline evaporates and to heat-up the generator's rotor to prevent it from rusting. The reason the first oil change at 50 hours is to remove the break-in oil and break-in contaminants from the engine as it has no oil filter. So, just change the oil when you change the engine's oil.