MAINTENANCE EVERY 250 OPERATING HOURS MAINTENANCE EVERY 250 OPERATING HOURS All maintenance operations to be performed after 10, 50 and 100 hours of operation also fall into this maintenance category. CHANGING THE ENGINE OIL AND OIL FILTER CARTRIDGE See chapter "Maintenance After the First 50 Operating Hours". CHECKING THE V-BELT CONDITION See chapter "Maintenance After the First 50 Operating Hours". CHECKING AND ADJUSTING THE V-BELT TENSION See chapter "Maintenance After the First 50 Operating Hours". 7-46