Engine Does Not Rotate Smoothly (Hunting) - Komatsu 95-2 Series Shop Manual

TROUBLESHOOTING
S-5 Engine does not rotate smoothly (hunting)
General causes why engine does not rotate
smoothly
• Air in fuel system
• Defective governor mechanism
• Defective electric governor mechanism
fl If hunting does not occur when the rod
between the governor motor and the in-
jection pump is disconnected, trouble-
shoot by using the electrical system trou-
bleshooting (E mode).
Legend
: Possible causes (judging from Questions and check items)
: Most probable causes (judging from Questions and Check items)
: Possible causes due to length of use (used for a long period)
: Items to confirm the cause.
Confirm recent repair history
Degree of use of machine
Condition of hunting
Replacement of filters has not been carried out according
to Operation Manual
Fuel tank is found to be empty
Rust, water are found when fuel tank is drained
Leakage from fuel piping
When feed pump is operated,
1) No response, light, return is quick
2) No response, light, return is normal
Engine speed sometimes rises too far
Engine is sometimes difficult to stop
Seal on injection pump has come off
When governor lever is moved it is found to be stiff
When injection pump is tested, governor is found to be
improperly adjusted
When control rack is pushed, it is found to be heavy, or
does not return
When fuel cap is inspected directly, it is found to be clogged
When feed pump strainer is inspected directly, it is found to
be clogged
When fuel filter, strainer are inspected directly, they are
found to be clogged
95-2 SERIES
Operated for long period
Occurs at a certain speed range
Occurs at low idling
Occurs even when speed is raised
Occurs on slopes
Remedy
S-5
Causes
12-113
12-113
1