Are there abnormal vibrations or noise?Depending on the hull structure, engine andhull resonance may suddenly increase atcertain engine speed ranges, causing heavyvibrations. Avoid operation in this speedrange. If any abnormal sounds are heard,stop the engine and inspect for the cause.Alarm sounds during operation.If the alarm sounds during operation, lowerthe engine speed immediately, check thewarning lamps and stop the engine forrepairs.Is there water, oil or fuel leakage? Arethere any loose bolts or connections?Check the engine room daily for any leaksor loose connections.Is there sufficient fuel in the fuel tank?Refill the fuel tank in advance to avoidrunning out of fuel. If the tank runs out of fuel,bleed the fuel system.See Air Bleeding fromthe Fuel System After Starting Failure onpage 34.TROUBLESHOOTINGINFORMATIONIf the engine does not operate properly, referto the Troubleshooting Chart on page 61or see your authorized Yanmar Marinedealer or distributor.Supply the authorized Yanmar Marinedealer or distributor with the followinginformation:• Model name and serial number of yourengine• Boat model, hull material, size (tons)• Use, type of boating, number of hours run• Total number of operation hours (refer tohour meter), age of boat• The operating conditions when theproblem occurs:• Engine rpm• Color of exhaust smoke• Type of diesel fuel• Type of engine oil• Any abnormal noises or vibration• Operating environment such as highaltitude or extreme ambienttemperatures• Engine maintenance history andprevious problems• Other factors that contribute to theproblemTROUBLESHOOTING60 GM Series Operation Manual© 2007 Yanmar Marine International