We have a maintenance contract provided by the seller. Every 6 months, the tech changes oil, oil filter, spark plugs, and air filter; checks the sealed battery, battery charger, output voltage, output frequency, and connections.
The service has been unreliable inasmuch as it always requires me to call them to remind them that the service is overdue. This has happened right from the beginning in 2005. They're always late.
But I've been afraid to fuss because, who else would perform these services? I'm too old and wouldn't have a clue about the electrical checks anyway. Do you think that an electrician would perform these tasks, or is the changing of oil, plugs, filters beneath them? Yellow pages advertises electricians who work with generators, but I think that this refers to inside work on the generator's circuit breaker box when needed.