Repair Service Manual

REPAIR MANUAL
1
KUBOTA Z402 and Z602 engines
REPAIR (cont’d)
Anomaly
Possible cause
Solution
The engine does
not run regularly
Clogged or dirty fuel filter
Clean or change
Clogged air filter
Clean or change
Fuel leak due to bad tightening of a
fastening nut on the injector duct
Retighten the nut
Bad operation of the injection pump
Repair or change
Bad injector opening pressure
Adjust
Stuck or clogged injector
Repair or change
Faulty regulator operation
Repair
Exhaust gases
black, or dark grey
Excess motor oil
Reduce to level specified
Wear or sticking of a piston ring and a
jacket
Repair or change
Bad injection timing
Adjust
Bad compression
Adjust neutral spaces
Overload
Reduce the load
Bad quality fuel
Use the fuel specified
Clogged fuel filter
Clean or change
Clogged air filter
Clean or change
Faulty injector
Repair or change the injector
Insufficient power
Bad injection timing
Adjust
The engine moving parts seem to be seized
Repair or change
Irregular fuel injection
Repair or change the injection pump
Faulty injector
Repair or change the injector
Lack of compression
Change the cylinder head gasket, tighten
the cylinder head screw, the glow plug and
injector holder
Excessive oil
consumption
The cutting gap is set in the same direction
for all piston rings
Modify the location of the cutting gap
Worn or stuck oil control ring
Change
Worn piston ring groove
Change the piston
Worn valve stem and guide
Change
Worn crankshaft main bearings or trunnion
bearings
Change
Oil leaked caused by a faulty lining or
sealing
Change