Yanmar 3JH4E Service Manual page 145

Fault
2. Engine starts, but
immediately stops.
3. Engine's Defective
output is injection timing
insufficient. and other
failures.
Nozzle
movements is
defective.
Injection pump
is defective.
4. Idling is rough.
5. Engine runs at high
speeds, but cuts out at low
speeds.
6. Engine doesn't reach max.
speed
Cause
(1) Fuel pipe is clogged.
(2) Fuel filter is clogged.
(3) Improper air- tightness of the fuel pipe
connection. or pipe is broken and air is being
sucked in.
(4) Insufficient fuel delivery from the feed pump
(1) Knocking sounds caused by improper (too
fast) injection timing.
(2) Engine overheats or emits large amount of
smoke due to improper (to slow) injection
timing.
(3) Insufficient fuel delivery from feed pump.
(1) Case nut loose.
(2) Defective injection nozzle performance.
(3) Nozzle spring is broken.
(4) Excessive oil leaks from nozzle.
(1) Max delivery limit boll is screwed in too far.
(2) Plunger is worn
(3) Injection amount is not uniform.
(4) Injection timings are not even.
(5) The 1st and 2nd levers of the governor and
the control rack or the injection pump are
improperly lined up.
(6) Delivery stopper is loose.
(7) Delivery packing is defective.
(8) Delivery valve seat is defective.
(9) Delivery spring is broken.
(1) Movement of control rack is defective.
1) Stiff plunger movement or sticking.
2) Rack and pinion fitting is defective.
3) Movement of governor is improper
4) Delivery stopper is too tight.
(2) Uneven injection volume.
(3) Injection timing is defective.
(4) Plunger is worn and fuel injection adjustment
is difficult.
(5) Governor spring is too weak.
(6) Feed pump can't feed oil at low speeds.
(7) Fuel supply is insufficient at low speeds due
to clogging of fuel filter.
(1) The wire or rod of the accel. is caught.
(2) Control rack is caught and can't be moved.
(1) Governor spring is broken or excessively
worn.
(2) Injection performance or nozzle is poor
129
6. FUEL INJECTION EQUIPMENT
Remedy
Clean
Disassemble and clean,
or replace the element
Replace packing repair
pipe
Repair or replace
Inspect and adjust
Inspect and adjust
Repair or replace
Inspect and retighten
Repair or replace nozzle
Replace
Replace nozzle assembly
Adjust
Replace
Adjust
Adjust
Repair
Inspect and retighten
Replace packing
Repair or replace
Replace
Repair or replace
Repair
Repair
Inspect and adjust
adjust
adjust
Replace
Replace
Repair or replace
Disassemble and clean,
or replace element
Inspect and repair
Inspect and repair
Replace
Repair or replace