Maintenance51tor before operation.EMU28511Replacement partsIf replacement parts are necessary, use onlygenuine Yamaha parts or parts of equivalentdesign and quality. Any part of inferior qualitymay malfunction, and the resulting loss ofcontrol could endanger the operator andpassengers. Yamaha genuine parts and ac-cessories are available from your Yamahadealer.EMU34150Severe 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 Brief periods of rapid acceleration and de-celeration followed by engine shut off be-fore the engine has reached properoperating temperature 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.