Preventative                 Maintenance 

Visual inspection 
Check intake and exhaust for obstructions 
Check fault codes 
Check battery (Cold Cranking Amps) 
Check oil level / oil condition 
Check coolant level and condition (Only on liquid cooled models)
Replace air filter 
Replace spark plugs 
Valve lash adjustment if needed 
Manual start (No load transfer)
Verify voltage and frequency outputs 
Adjust engine speed 
Change oil using quality brand synthetic oil and replace oil filter 
Transfer to generator power with a simulated power outage
Transfer back to utility power 
Re-level generator (when necessary)

Clean outer cabinet of generator and associated equipment