Yanmar 3JH4E, Service Manual

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3. Precautions for Service Work
(1) Precautions for Safety
Read the safety precautions given at the beginning of this manual carefully and always mind safety in
work.
(2) Preparation for Service Work
Preparation is necessary for accurate, efficient service work. Check the customer ledger file for the
history of the engine.
• Preceding service date
• Period / operation hours after preceding service
• Problems and actions in preceding service
• Replacement parts expected to be required for service
• Recording form / check sheet required for service
(3) Preparation before Disassembly
• Prepare general tools, special service tools, measuring instruments, oil, grease, non-reusable parts,
and parts expected to be required for replacement.
• When disassembling complicated portions, put match-marks and other marks at places not
adversely affecting the function for easy reassembly.
(4) Precautions in Disassembly
• Each time a parts is removed, check the part installed state, deformation, damage, roughening,
surface defect, etc.
• Arrange the removed parts orderly with clear distinction between those to be replaced and those to
be used again.
• Parts to be used again shall be washed and cleaned sufficiently.
• Select especially clean locations and use clean tools for disassembly of hydraulic units such as the
fuel injection pump.
(5) Precautions for Inspection and Measurement
Inspect and measure parts to be used again as required to determine whether they are reusable or not.
(6) Precautions for Reassembly
• Reassemble correct parts in correct order according to the specified standards (tightening torques,
and adjustment standards). Apply oil important bolts and nuts before tightening when specified.
• Always use genuine parts for replacement.
• Always use new oil seals, O-rings, packing and cotter pins.
• Apply sealant to packing depending on the place where they are used. Apply of grease to sliding
contact portions, and apply grease to oil seal lips.
(7) Precautions for Adjustment and Check
Use measuring instruments for adjustment to the specified service standards.