Kohler marine genset service intervals

Kohler marine gensets (5EFOZ, 8EFOZ, 20EFOZ, 32EFOZD series) follow a 100 or 250-hour cycle depending on model. Oil and oil filter: every 100 hours on the smaller EFOZ units, every 250 on the 20 and 32 kW. Fuel filter (Kohler GM77220 or equivalent): every 500 hours. Air filter: inspect every 250 hours, replace when dirty. Coolant: every 3 years or 2000 hours, Fleetguard ES Compleat OAT (orange) is Kohler-approved. Impeller: every 500 hours or annually, Kohler impellers are Jabsco-based, plentiful spares. Anodes (heat exchanger and aftercooler pencil zincs): inspect every 250 hours. Valve lash: every 500 hours (0.006 in intake, 0.008 in exhaust cold). Belt: 250 hours. Load-testing rule: Kohler recommends 30 to 40 percent of rated load for at least 30 minutes weekly to prevent wet stacking. Below 25 percent for extended runs causes unburned fuel to accumulate in the exhaust, glazing cylinder walls and fouling injectors. Common failure: the low-voltage/frequency shutdown trips on undersized inverters transferring at cold-start, check inverter transfer timing before condemning the genset.