Sailing Jibseavideo
How to Replace a Fresh Water Pump on Sailboat - Yanmar Diesel Engine - Ep 10
11 November 2020 · 9 min · 23K views
What this video covers
Replacing a failed raw water pump on a Yanmar 4J-HTE diesel engine requires draining the coolant system and removing the alternator and pulley housing.0:03 To prevent the pulley from spinning during removal, keep the drive belt attached while cracking the four housing bolts loose.1:07 After removing the belt and alternator, disconnect the thermostat, heat exchanger piping, and sensors from the pump assembly.2:43 Note that bolt lengths vary, and components may be seized after long-term use; applying heat can assist in removing stubborn sensors or fittings.3:29 When reinstalling, fill the coolant system carefully to avoid air pockets, which cause immediate engine overheating.6:09 Use the water heater hose to bleed the system, then run the engine for short 20-second intervals to burp remaining air from the temperature sensor housing.7:37 A properly tensioned drive belt should have approximately 10 millimeters of deflection.7:10 Bearing failure in the pump is indicated by leaking from the weep hole, crusty deposits, or a non-linear, jumpy feel when spinning the pulley by hand.4:29
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