Maintenance62EMU34151Severe operating conditionsSevere operating conditions involve one ormore of the following types of operation on aregular basis: Operating continuously at or near maxi-mum engine speed (rpm) for many hours Operating continuously at a low enginespeed (rpm) for many hours Operating without sufficient time for en-gine to warm up and cool down Frequent quick acceleration and decelera-tion Frequent shifting Frequently starting and stopping the en-gine(s) Operation that fluctuates often betweenlight and heavy cargo loadsOutboard motors operating under any ofthese above conditions require more fre-quent maintenance. Yamaha recommendsthat you do this service twice as often asspecified in the maintenance chart. For ex-ample, if a particular service should be doneat 50 hours, do it instead at 25 hours. Thiswill help prevent more rapid deterioration ofengine components.