What the manufacturer maintenance schedule actually says
A standby generator involves utility-voltage electricity, fuel gas, moving parts, and equipment that can start automatically. This page describes what manufacturer documents say an owner can observe or set from the controls — it is not repair instructions. Follow the safety warnings and shutdown steps in your unit's manual before approaching the unit, and leave work inside the equipment, transfer switch, or fuel and electrical systems to an authorized dealer or licensed electrician.
Why the schedule matters
- Generac's 10–24 kW owner's manual states that regular maintenance will improve performance and extend engine and equipment life, and that emissions-critical maintenance (servicing the air filter and spark plugs per the service schedule) must be performed as scheduled for the emissions warranty to remain valid. Maintenance, replacement, or repair of emissions control devices and systems may be performed by any repair shop or person of the owner's choosing — but to obtain emissions-control warranty service free of charge, the work must be performed by an Independent Authorized Service Dealer. (Generac Power Systems, Inc. archived source, retrieved 2026-07-09; Verified Fact; EV-GEN-EVO-0002#C4)
Maintenance schedule (as published by the manufacturer)
- Both Generac air-cooled owner's manuals publish the same owner-facing service tiers: Schedule A (replace engine oil and oil filter; check battery condition, electrolyte level, and state of charge) every two years or 200 hours of operation, and Schedule B (adds air-filter replacement, spark-plug service, and valve-clearance inspection where applicable) every four years or 400 hours. Engine oil and filter are first changed after 25 hours of operation, and yearly (or every 100 hours) in sustained cold (below 40°F) or hot (above 85°F) conditions. Generac recommends all maintenance work be performed by an Independent Authorized Service Dealer, and the controller prompts when Schedule A or B is due. The 2020 manual exempts 14 and 18 kW units with 816cc engines from valve adjustment. (Generac Power Systems, Inc. archived source 1; archived source 2, retrieved 2026-07-09; Verified Fact; EV-GEN-EVO-0002#C2)
- Kohler's RCA service schedules differ by model within the same product line: on 14 kW models the oil is changed yearly or every 100 hours and the filter yearly or every 200 hours, while on 20 and 26 kW models a standard oil change is yearly or every 150 hours (26 kW with premium oil: every two years or 300 hours) with the filter replaced at each oil change; oil level is checked every 8 hours of operation on 14/20 kW models but every 24 hours on the 26 kW. Kohler directs owners to have an authorized dealer service the generator at the designated intervals, to service more frequently under extreme weather, long operating hours, or dusty/dirty conditions, and lists weekly generator exercise in the schedule. (Kohler Co. archived source, retrieved 2026-07-09; Verified Fact; EV-KOH-ERR-0001#C2)
Typical service costs
Verified guidance for this section has not been published yet.
When to call a professional
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Safety and warranty considerations
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