Infolinks 2014

2001 Polaris Sportsman 400-500 DUSE & H.O. Troubleshooting repair guide

Engine Turn Over But Fail to Start
No fuel
Dirt in fuel line or filter
Fuel will not pas through fuel valve
Fuel pump inoperative/restricted
Tank vent plugged
Carb starter circuit
Engine flooded
Low compression (high cylinder leakage)
No spark (Spark plug fouled)
Engine Doe Not Turn Over
Dead battery
Starter motor doe not turn
Engine seized, rusted, or mechanical failure
Engine Run But Will Not Idle
Restricted carburetor pilot system
Carburetor misadjusted
Choke not adjusted properly
Low compression
Crankcase breather restricted
Engine Idle But Will Not Rev Up
Spark plug fouled/weak spark
Broken throttle cable
Obstruction in air intake
Air box removed (reinstall all intake components)
Incorrect or restricted carburetor jetting
ETC switch limiting speed
Reverse speed limiter limiting speed
Carburetor vacuum slide sticking/diaphragm damaged
Incorrect ignition timing
Restricted exhaust system
Engine Ha Low Power
Spark plug fouled
Cylinder, piston, ring, or valve wear or damage (check compression)
PVT not operating properly
Restricted exhaust muffler
Carburetor vacuum slide sticking/diaphragm damaged
Dirty carburetor
Piston Failure – Scoring
Lack of lubrication
Dirt entering engine through crack in air filter or ducts
Engine oil dirty or contaminated

Excessive Smoke and Carbon Buildup
Excessive piston-to-cylinder clearance
Wet sumping
Worn rings, piston, or cylinder
Worn valve guide or seals
Restricted breather
Air filter dirty or contaminated
Low Compression
Decompressor stuck
Cylinder head gasket leak
No valve clearance or incorrectly adjusted
Cylinder or piston worn
Piston ring worn, leaking, broken, or sticking
Bent valve or stuck valve
Valve spring broken or weak
Valve not seating properly (bent or carbon accumulated on sealing surface)
Rocker arm sticking
ETC or speed limiter system malfunction
Fouled spark plug or incorrect plug or plug gap
Carburetion faulty – lean condition
Exhaust system air leaks
Ignition system faulty:
Spark plug cap cracked/broken
Ignition coil faulty
Ignition or kill switch circuit faulty
Ignition timing incorrect
Sheared flywheel key
Poor connection in ignition system
System wiring wet
Valve sticking
Air leak in intake
Lean condition

Low coolant level
Air in cooling system
Wrong type of coolant
Faulty pressure cap or system leaks
Restricted system (mud or debri in radiator fin or restriction to air flow, passage blocked in
radiator, lines, pump, or water jacket)
Lean mixture (restricted jets, vents, fuel pump or fuel valve)
Fuel pump output weak
Restricted radiator (internally or cooling fins)
Water pump failure
Cooling system restriction
Cooling fan inoperative or turning too slowly (perform current draw test)
Ignition timing misadjusted
Low oil level
Spark plug incorrect heat range
Faulty hot light circuit
Thermostat stuck closed or not opening completely
Temperature Too Low
Thermostat stuck open
Leak at Water Pump Weep Hole
Faulty water pump mechanical seal (coolant leak)
Faulty pump shaft oil seal (oil leak)

Fuel Starvation/Lean Mixture
Symptoms: Hard start or no start, bog, backfire, popping through intake / exhaust, hesitation, detonation, low
power, spark plug erosion, engine run hot, surging, high idle, idle speed erratic.
No fuel in tank
Restricted tank vent, or routed improperly
Fuel line or fuel valve restricted
Fuel filter plugged
Carburetor vent line(s) restricted
Plugged or restricted inlet needle and seat screen or inlet passage
Clogged jet or passages
Float stuck, holding inlet needle closed or inlet needle stuck
Float level too low
Fuel pump inoperative
Air leak at impulse line
Restricted impulse line (kinked, pinched)
Intake air leak (throttle shaft, intake ducts, airbox or air cleaner cover)
Ruptured vacuum slide diaphragm, Vacuum slide stuck closed or sticky
Improper spring
Jet needle position incorrect
Incorrect pilot screw adjustment
Rich Mixture
Symptoms: Foul spark plugs, black, sooty exhaust smoke, rough idle, poor fuel economy, engine run rough/
misses, poor performance, bog, engine load up, backfire.
Air intake restricted (inspect intake duct)
Air filter dirty/plugged
Choke plunger sticking, incorrectly adjusted choke
Choke cable binding or improperly routed
Incorrect pilot air/fuel screw adjustment
Faulty inlet needle and seat
Faulty inlet needle seat O-Ring
Float level too high
Poor fuel quality (old fuel)
Loose jets
Worn jet needle/needle jet or other carburetor parts
Dirty carburetor (air bleed passage or jets)
Weak or damaged vacuum piston return spring
Fouled spark plug
Poor Idle
Symptoms: Idle too high.
Idle adjusted improperly/idle mixture screw damaged
Sticky vacuum slide
Throttle cable sticking, improperly adjusted, routed incorrectly
Choke cable sticking, improperly adjusted, routed incorrectly

Idle Too Low
Choke cable bending or incorrectly adjusted
Idle speed set incorrectly
Idle mixture screw misadjusted or damaged
Belt dragging
Ignition timing incorrect
Worn jet needle/needle jet
Erratic Idle
Choke cable bending or incorrectly adjusted
Throttle cable incorrectly adjusted
Air leaks, dirty carburetor passage (pilot circuit)
Pilot mixture screw damaged or adjusted incorrectly
Tight valves
Ignition timing incorrect
Belt dragging
Dirty air cleaner
Engine worn
Spark plug fouled
Idle speed set incorrectly (speed limiter)
Worn jet needle/needle jet


Check the following item when shifting difficulty i encountered.
Idle speed adjustment
Transmission oil type/quality
Transmission torque stop adjustment
Engine torque stop adjustment
Drive belt deflection
Loose fastener on rod ends
Loose fastener on selector box
Worn rod ends, clevi pins, or pivot arm bushings
Linkage rod adjustment and rod end positioning
Shift selector rail travel
*Worn, broken or damaged internal transmission components


Brake Squeal
Dirty/contaminated friction pads
Improper alignment
Worn disc
Worn disc splines
Poor Brake Performance
Air in system
Water in system (brake fluid contaminated)
Caliper/disc misaligned
Caliper dirty or damaged
Brake line damaged or lining ruptured
Worn disc and/or friction pads
Incorrectly adjusted lever
Incorrectly adjusted stationary pad
Worn or damaged master cylinder or components
Improper clearance between lever and switch
Lever Vibration
Disc damaged
Disc worn (runout or thicknes variance exceed service limit)
Caliper Overheat (Brake Drag)
Compensating port plugged
Pad clearance set incorrectly
Auxiliary brake pedal incorrectly adjusted
Brake lever or pedal binding or unable to return fully
Parking brake left on
Residue build up under caliper seals
Operator riding brakes
Brake Lock
Alignment of caliper to disc.


No Spark, Weak or Intermittent Spark
Spark plug gap incorrect
Fouled spark plug
Faulty spark plug cap or poor connection to high tension lead
Related wiring loose, disconnected, shorted, or corroded
Engine Stop switch or ignition switch faulty
ETC switch misadjusted or faulty
Terminal board or connection wet, corroded
Poor ignition coil ground (e.g. coil mount loose or corroded)
Faulty stator (measure resistance of all ignition related windings)
Incorrect wiring (inspect color coding in connector etc)
Faulty ignition coil winding (measure resistance of primary and secondary)
Worn magneto (RH) end Crankshaft bearings
Sheared flywheel key
Flywheel loose or damaged
Trigger coil air gap too wide (where applicable) – should be .016-.040″ (.4-1.0 mm)
Excessive crankshaft runout on magneto (RH) end – should not exceed .0024″
Faulty CDI module


tarter Motor Doe Not Turn
Battery discharged – low specific gravity
Loose or faulty battery cable or corroded connection (see Voltage Drop Tests)
Related wiring loose, disconnected, or corroded
Poor ground connection at battery cable, starter motor or starter solenoid (see Voltage Drop
Faulty starter button
Faulty ignition switch (Do other system function?)
Faulty starter solenoid or starter motor.
Engine problem – seized or binding (Can engine be rotated easily with recoil starter?)
tarter Motor Turn Over Slowly
Battery discharged – low specific gravity
Excessive circuit resistance – poor connection (see Voltage Drop Test below)
Engine problem – seized or binding (Can engine be rotated easily with recoil starter?)
Faulty or worn brushe in starter motor
Automatic compression release inoperative
tarter Motor Turn – Engine Doe Not Rotate
Faulty starter drive
Faulty starter drive gear or starter motor gear
Faulty flywheel gear or loose flywheel


KYMCO DINK CLASSIC 200 Troubleshooting repair guide


Oil level too low Poor lubrication pressure
• Natural oil consumption • Oil level too low
• Oil leaks • Clogged oil filter or oil passage
• Worn piston rings • Faulty oil pump
• Worn valve guide
• Worn valve guide seal
Oil contamination
• Oil not changed often enough
• Faulty cylinder head gasket
• Loose cylinder head bolts


• The poor cylinder head operation can be diagnosed by a compression test or by tracing engine
top-end noises.
Poor performance at idle speed White smoke from exhaust muffler
• Compression too low • Worn valve stem or valve guide
• Damaged valve stem oil seal
Compression too low
• Incorrect valve clearance adjustment Abnormal noise
• Burned or bend valves • Incorrect valve clearance adjustment
• Incorrect valve timing • Sticking valve or broken valve spring
• Broken valve spring • Damaged or worn camshaft
• Poor valve and seat contact • Worn cam chain tensioner
• Leaking cylinder head gasket • Worn camshaft and rocker arm
• Warped or cracked cylinder head
• Poorly installed spark plug
Compression too high
• Excessive carbon build-up in combustion


• When hard starting or poor performance at low speed occurs, check the crankcase breather for
white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken.
Compression too low or uneven
compression Excessive smoke from exhaust muffler
• Worn or damaged cylinder and piston rings • Worn or damaged piston rings • Worn, stuck or broken piston rings • Worn or damaged cylinder and piston
Compression too high Abnormal noisy piston
• Excessive carbon build-up in combustion • Worn cylinder, piston and piston rings
chamber or on piston head • Worn piston pin hole and piston pin

• Incorrectly installed piston


Engine starts but motorcycle won‘t move Lack of power
• Worn drive belt • Worn drive belt
• Broken ramp plate • Weak driven face spring
• Worn or damaged clutch lining • Worn weight roller
• Broken driven face spring • Faulty driven face
Engine stalls or motorcycle creeps
• Broken clutch weight spring


Engine starts but motorcycle won‘t move
• Damaged transmission
• Seized or burnt transmission
Abnormal noise
• Worn, seized or chipped gears
• Worn bearing
Oil leaks
• Oil level too high
• Worn or damaged oil seal


Refer to page 1-27 for A.C. generator troubleshooting.
Starter motor rotates but engine does not start
• Faulty starter clutch
• Starter motor rotates reversely
• Weak battery


Excessive engine noise
• Excessive bearing play
• Excessive crankpin bearing play
• Worn piston pin and piston pin hole


Engine temperature too high Coolant leaks
• Faulty temperature gauge or thermosensor • Faulty pump mechanical (water) seal
• Faulty radiator cap • Deteriorated O-rings
• Faulty thermostat • Damaged or deteriorated water hoses
• Insufficient coolant
• Passages blocked in hoses or water jacket
• Clogged radiator fins
• Passages blocked in radiator
• Faulty water pump
Temperature gauge pointer does not register
the correct coolant temperature
• Faulty temperature gauge or thermosensor
• Faulty thermostat


Engine does not start Engine idles roughly, stalls or runs poorly
• No fuel in tank • Incorrect idle speed
• Restricted fuel line • Rich mixture
• Too much fuel getting to cylinder • Lean mixture
• Clogged air cleaner • Clogged air cleaner
• Contaminated fuel • Intake air leak
• Faulty fuel pump • Contaminated fuel
• Faulty air-cut off valve
• Damaged vacuum tube and connectors
• Damaged carburetor insulator

Throttle does not open fully, so engine stalls Rich mixture
• Damaged vacuum piston diaphragm • Auto bystarter valve opens excessively
• Clogged diaphragm hole • Faulty float valve
• Float level too high
Lean mixture • Clogged air jets
• Clogged fuel jets • Auto bystarter valve set plate installed in
• Clogged fuel tank cap breather hole the wrong groove
• Clogged fuel filter •Clogged air cleaner
• Bent, kinked or restricted fuel line
• Faulty float valve
• Float level too low
• Faulty fuel pump or insufficient output


Hard steering (heavy) Front wheel wobbling
• Excessively tightened steering stem top • Bent rim
cone race • Loose front axle
• Broken steering balls • Bent spoke plate
• Insufficient tire pressure • Faulty tire
Steers to one side or does not track straight • Improperly tightened axle nut
• Uneven front shock absorbers Soft front shock absorber
• Bent front fork • Weak shock springs
• Bent front axle or uneven tire • Insufficient damper oil
Poor brake performance Front shock absorber noise
• Worn brake pads • Slider bending
• Contaminated brake pad surface • Loose fork fasteners
• Deformed brake disk • Lack of lubrication
• Air in brake system
• Deteriorated brake fluid
• Worn brake master cylinder piston oil seal
• Clogged brake fluid line
• Unevenly worn brake caliper


Rear wheel wobbling Poor brake performance
• Bent rim • Air in brake system
• Faulty tire • Deteriorated brake fluid
• Axle not tightened properly • Contaminated brake pad surface
• Worn brake pads
Soft rear shock absorber • Clogged brake fluid line
• Weak shock absorber spring • Deformed brake disk
• Damper oil leaks • Unevenly worn brake caliper
Rear wheel noise
• Worn rear wheel axle bearings
• Worn rear fork bearings
• Deformed rear fork


No power Intermittent power
• Dead battery • Loose battery cable connection
• Disconnected battery cable • Loose charging system connection
• Fuse burned out • Loose connection or short circuit in
• Faulty ignition switch ignition system
Low power Charging system failure
• Weak battery • Loose, broken or shorted wire or connector
• Loose battery connection • Faulty regulator/rectifier
• Charging system failure • Faulty A.C. generator


No spark at plug Engine starts but turns poorly
• Faulty spark plug • Ignition primary circuit • Poorly connected, broken or shorted wire —Faulty ignition coil • Faulty ignition switch —Poorly connected wire or connector • Faulty ignition coil —Poorly contacted ignition switch • Faulty CDI unit • Ignition secondary circuit • Faulty A.C. generator —Faulty ignition coil
—Faulty spark plug —Faulty high-tension wire
—Poorly insulated plug cap
• Improper ignition timing
—Faulty A.C. generator
—Stator not installed properly
—Faulty CDI unit


Starter motor won‘t turn Lack of power
• Fuse burned out • Weak battery
• Weak battery • Loose wire or connection
• Faulty ignition switch • Foreign matter stuck in starter motor
• Faulty starter clutch or gear
• Faulty front or rear stop switch
• Faulty starter relay Starter motor rotates but engine does
• Poorly connected, broken or shorted wire not start
• Faulty starter motor • Faulty starter pinion
• Starter motor rotates reversely
• Weak battery


Lights do not come on when ignition Temperature gauge does not register
switch is “ON” correctly
• Burned bulb • Faulty temperature gauge
• Faulty switch • Faulty thermosensor
• Poorly connected, broken or shorted wire • Broken or shorted wire between
temperature gauge and thermosensor
Fuel gauge pointer does not move or
register correctly
• Faulty fuel gauge
• Faulty fuel unit
• Poorly connected wire between fuel
gauge and fuel unit
• Fuse burned out


High CO at idle speed
1. Damaged or clogged reed valve
2. Damaged or clogged air injection cut-off valve
3.Clogged air cleaner
Backfiring at sudden deceleration
1. Damaged reed valve (malfunction)
2. Faulty air injection cut-off valve (unable to close)
3.Carburetor incorrectly adjusted
4. Faulty air cut-off valve
5. Leaking vacuum tube
Exhaust muffler noise
1. Faulty air injection cut-off valve
2.Broken vacuum tube
3. Faulty reed valve


1)Set the long tiller handle assembly on the mount  frame and tighten the two 10 mm washers and two 10mm self-locking nuts.
2)Tighten the two 10 mm self-locking nuts to the speci- fied torque.
TORQUE: 34 N.m (3.5 kgf-m, 25 Ibf-ft)




3) Pass the tiller handle wire harness through the under case grommet A.

4) Pass the throttle cable and shift cable through the under case grommet A. · Pass the throttle cable through the inner side of the under case grommet A and the shift cable through the side close to the opening.

5) Set the throttle cable and shift cable in the cable plate by aligning the groove in each cable with the cutout in the cable set plate.

6) Set the under case grommet A, tiller handle wire harness, throttle cable and shift cable as a set in the engine under case.

7) Secure the tiller handle wire harness with the wire band clip.

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Cause and digging machines use hydraulic leak Notes

Engaged in construction machinery friends certainly often been plagued by the problem of leakage of hydraulic cylinder for excavator, a hydraulic cylinder once the leak, there will be a slow lifting, digging force shortage and so on. So digging machine hydraulic leak what are the reasons for it? We should pay attention to what time and use the excavator to avoid hydraulic leak it?

Under normal circumstances, the leakage of hydraulic cylinder divided into two kinds of leakage and leakage. If we look closely we can determine the cause of the external leak. The reason for determination of hydraulic cylinder internal leakage is more difficult, because the internal leakage site we are not directly observable.

So then, we have to say something simple hydraulic internal leakage and external leakage causes.

An external leak.

1, the projecting end of the piston rod with the piston rod seal is damaged, mostly due to galling caused by the piston cylinder, but also caused by aging.

2, with the piston rod end and cylinder seal is damaged, this is due to the long-term use of sealed seal caused by aging, many are squeezed too much force to damage the seal on the cover, there is a lot of domestic production of hydraulic cylinders manufacturers design caused by the irrational, in most cases, the manufacturers in order to save costs caused.

3, the cylinder out of the pipe joints can also cause cracking of hydraulic leaks.

4, there are oil spills caused by defective cylinder or the cylinder end cap.

5, the rod was pulled from the tank, pit points.

6, oil deterioration of the cylinder temperature anomalies increased, prompting aging seals.

7, often exceeding the scope of the use of cylinder pressure caused by oil spills.

Second, the internal leakage.

1, wear badly worn piston rings, causing friction between the piston and cylinder, and finally pulled cylinder, piston and seal.

2, the long-term use of the seal failure, piston seal (Multi Yes Yes U, V, Y-ring, etc.) aging.

3, the hydraulic oil is dirty, a lot of impurities into the cylinder piston seal wear to bad, usually iron or other foreign matter.

By simply described above, we can see that, in addition to long-term use of aging caused by seal than the other as long as we usually pay attention to maintenance work, hydraulic oil leak problem can be avoided. So we need to take advantage of the excavator working time and pay attention to what matters it? Here we have to talk briefly.

Note the use of the hydraulic cylinder.

Know the hydraulic oil spills cause, then the question is, when we use the hydraulic cylinder should pay attention to what the problem? Next, we say Precautions for the use of hydraulic cylinders.

1, we have to pay attention to protection normally use a good rod outer surface to prevent bump and scratch damage to seals, and now some of the construction machinery will be designed with a protective plate cylinder, although there are, but we still have to pay attention to prevent the usual bump and scratched. In addition, I also need to regularly clean the dust seal dynamic sealing fuel tanks and exposed parts of the sediment on the piston rod to prevent the piston rod attached to the surface difficult to clean the dirt into the cylinder inside, causing the piston, cylinder or seals damage.

2, normal use, we must pay attention to regular checks of each threaded joints, bolts, etc., found loose immediately tightened well. Because these places can also cause loose hydraulic leak, which for personnel engaged in construction machinery is well understood.

3, often lubricated coupling parts to prevent corrosion or normal wear and tear without oil is what we need to pay attention. Especially for some parts of corrosion phenomena, we should be in time to avoid corrosion caused by hydraulic oil spills.

4, when normal maintenance, we should note that the hydraulic oil should be changed regularly, promptly filter cleaning system to ensure the cleanliness of hydraulic oil, which is to extend the service life of the hydraulic cylinder has a very important role.

5, in the ordinary work, we have to pay attention to control the temperature of the system, because the oil temperature is too high will reduce the life of the seal, and the long-term high oil temperature will seal permanent deformation, severe cases can make a seal failure.

6, usually when we each use, to conduct a full shrink the whole stretch of the trip 3-5 after commissioning work. The aim is to drain the air from the system, preheat the systems, which can effectively avoid the presence of air or water systems, resulting in a gas explosion in the cylinder block phenomenon, which would damage the seal, causing the fuel tank vent, etc. malfunction.

7, after each job is completed, we need to pay attention to the size of the arm and bucket kept in an optimum state, is to ensure that the hydraulic oil in the hydraulic cylinders all back to the hydraulic tank, ensure that the hydraulic cylinder is not withstand the pressure. Because hydraulic cylinder under pressure in one direction for a long time, can lead to damage to the seal.

In fact, I believe that friends engineering machinery industry precautions for use of hydraulic cylinders, there are many suggestions, the author here just to name a few of them, in the eyes of everybody experienced practitioners may be somewhat plain, but also hope that many of my friends you put a lot of valuable advice.

Summary: hydraulic cylinder hydraulic system is a very important thing, once the leak of hydraulic cylinder occurs, it will cause the machine to appear slowly lifting, digging weakness phenomenon, which seriously affect the work efficiency. Time is money in this community for years, I believe this is a lot of friends do not want to see. So please be kind to your hydraulic cylinder now!

Volvo ZL 402 serie service manual

This operating instruction manual serves as a guide for the correct use and maintenance of your ZL 402 serie c ,it must always be kept with the machine,the recommendations for operation, maintenance and the safety regulations must be thoroughly read before you start the manchine, work with the machine or perform maintenacne work.


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Bobcat A300 TURBO Service repair manual S/N 521111001 & Above

This is the most practical Service Repair Manual for the Bobcat A300 S/N 521111001 & Above. This DOWNLOAD contains of high quality diagrams and instructions on how to service and repair your Bobcat A300.

FOREWORD. . . . . . . . . . . . . . . . . . . . . . . . . . . II
SAFETY INSTRUCTIONS . . . . . . . . . . . . . . . . . . V
SERIAL NUMBER LOCATION . . . . . . . . . . . . .IX
DELIVERY REPORT. . . . . . . . . . . . . . . . . . . .. . . . . . . X
SAFETY AND MAINTENANCE. . . . . . . . . . 10-01
HYDRAULIC SYSTEM . . . . . . . . .. . . . . . 20-01
HYDROSTATIC SYSTEM . . . . . . . . . . . . 30-01
DRIVE SYSTEM . . . . . . . . . .  . . . . . . . . . . . 40-01
MAIN FRAME . . . . . . . . . . . . . 50-01
ELECTRICAL SYSTEM & ANALYSIS. . . . . . . . . .. . 60-01
ENGINE SERVICE . . . . . . . .  . . . . 70-01
SPECIFICATIONS. . . . . . . . . . . . SPEC-01

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bobcat MT52 MT55 Service Manual S/N A3WR11001 A3WT11001 A3WS1100 A3WU11001 & Above

This bobcat MT52 MT55  service manual is for the Bobcat loader mechanic. It provides necessary servicing and adjustment procedures for the Bobcat Mini loader and its component parts and systems. Refer to the Operation & Maintenance manual for operating instructions, Starting procedure, daily checks, etc.

FOREWORD. . . . . . . . . . .. . . . . . . . . . . . III
SAFETY INSTRUCTIONS . . . . . . . . . . . . . . . . V
SERIAL NUMBER LOCATION . . . . . . . . . . . . . . . .IX
DELIVERY REPORT. . . . . . . . . . . . . . . . . . . . . . . .IX
BOBCAT LOADER IDENTIFICATION. . . . . . . . . . . . . . X
SAFETY AND MAINTENANCE. . . . . . . . . 10-01
HYDRAULIC SYSTEM . . . . . . . . . 20-01
HYDROSTATIC SYSTEM . . . . . . .  . . . . . . 30-01
DRIVE SYSTEM . . . . . . . . . . . . . . . . . . . . . 40-01
MAIN FRAME . . . . . . . . . . . . . . . . . 50-01
ELECTRICAL SYSTEM & ANALYSIS. . . . . . . . . . 60-01
ENGINE SERVICE . . . . . . . . . . . . . . . . 70-01
SPECIFICATIONS. . . . . . .. . . . . . . . SPEC-01



  • No drive function
  • No drive on one side in both directions
  • No drive on one side in one direction
  • Machine does not drive in reverse
  • Machine does not move in straight line
  • Hydrostatic system overheating
  • Hydraulic/Hydrostatic warning light comes on.


1. Belt slippage.
2. Low or no charge pressure.
3. Sheared key on drive motor and/or loose castle bolt.
4. Hydrostatic system has fluid leak.
5. Steering linkage loose, damaged or needs adjustment.
6. Hydrostatic pressure relief valve is defective.
7. Hydrostatic pump has defect.
8. Hydrostatic motor has defect.
9. Hydrostatic fluid not at correct level.
10. Drive relief on hydrostatic pump is stuck open.
11. Inspect reverse speed adjustment.
12. Reverse stop linkage mechanism failure.
13. Steering lever is obstructed.
14. Restricted oil cooler.
15. Plugged case drain.
16. Hydraulic cooling fan not operable (Refer to Electrical Troubleshooting).
17. Electrical defect.
18. Hydraulic oil temp too high.


Battery looses charge.
Alternator will not charge.
Starter will not turn the engine.
Auxiliary blower fan will not run when auxiliaries are engaged.
Lift arm does not lower with the engine running and activation of the lift lever.
Electric fan not operating with engine running.


1. Alternator belt is loose or damaged.
2. Battery connections are dirty or loose.
3. Battery is weak or failed.
4. The ground is not correct in the electrical system.
5. The alternator has a failure.
6. Engine seizure.
7. Starter has a failure.
8. Neutral start circuit failure. (wiring, relay, solenoid, connectors)
9. Fuse had a failure.
10. Auxiliary lever engaged.
11. Left or right drive lever engaged.
12. Starter relay has a failure.
13. Electric fan circuitry failure.
14. Electric fan motor.
15. Lift arm circuit has a failure. (fuse, relay, solenoid)
16. Engine oil pressure circuit has a failure. (fuse, relay, solenoid, switch)
17. Low engine oil pressure.
18. Loose, disconnected or damaged wiring.
19. Lift control lever, not in neutral position.
20. Continuous auxiliary hydraulic shutoff lever is engaged.


Slow cranking speed.
Engine will not start.
Difficult to start.
No power from the engine.
Engine is mis-firing.
Too much fuel consumption.
Black exhaust.
Blue/White exhaust.
Low oil pressure.
Engine knocking.
Engine running rough.
High oil pressure.
Engine Overheating.
Too much crankcase pressure.
Poor compression.
Engine starts but does not stay running.
Engine does not shut off.


1. Battery capacity low. 31. Worn valves and seats.
2. Bad electrical connection. 32. Broken, worn or sticking piston rings.
3. Faulty starter motor. 33. Worn valve stems and guides.
4. Incorrect grade of oil. 34. Overly full air cleaner.
5. Low cranking speed. 35. Worn or damaged bearings.
6. Fuel tank empty. 36. Not enough oil in the oil pan.
7. Faulty stop control operation. 37. Gauge is not correct.
8. Plugged fuel line. 38. Oil pump worn.
9. Faulty fuel lift pump. 39. Pressure relief valve is open.
10. Plugged fuel filter. 40. Pressure relief valve is sticking closed.
11. Restriction in the air cleaner. 41. Broken relief valve spring.
12. Air in the fuel system. 42. Faulty suction pipe.
13. Faulty fuel injection pump. 43. Plugged oil filter.
14. Faulty fuel injectors. 44. Piston seizure.
15. Incorrect use of the glow plugs 45. Incorrect piston height.
16. Glow plugs not working. 46. Damaged fan.
17. Broken fuel injection pump drive. 47. Faulty engine mounting or loose mounting.
18. Incorrect fuel pump timing. 48. Faulty thermostat.
19. Incorrect valve timing. 49. Restriction in the water jacket.
20. Poor compression. 50. Loose fan belt.
21. Plugged fuel tank vent. 51. Plugged radiator.
22. Incorrect type or grade of fuel. 52. Faulty water pump.
23. Exhaust pipe restriction. 53. Plugged breather pipe.
24. Cylinder head gasket leaking. 54. Valve stem seals damaged.
25. Overheating. 55. Coolant level low.
26. Cold running. 56. Plugged oil pump pipe strainer.
27. Incorrect valve tappet adjustment. 57. Broken valve spring.
28. Sticking valves. 58. Hydraulics in Detent position or drive engaged.
29. Incorrect high pressure tubelines. 59. Faulty shut-down circuit. (See Troubleshooting on Page
30. Worn engine cylinder bores


Yanmar EM Industrial Diesel Engine Service Repair Manual instruction book

This is the most practical Service Repair Manual for the Original Factory Yanmar EM Industrial Diesel Engine Workshop Service Repair Manual Download ever compiled by mankind. This DOWNLOAD contains of high quality diagrams and instructions on how to service and repair your Yanmar.


  • 1.   Engine   Components   and   Functions
  • 2.   Fuel and   Lubrication   Oil
  • 3,   Precautions   for  Operating  a   New   Engine
  • 4.   Preparations   for   Starting
  • 5. operating instructions
  • 6.   Storage
  • 7.   Periodic   Inspection  and   Maintenance
  • 8.   How   to   Inspect   and   Maintain 15
  • 9.   Trouble Shooting

Yanmar EM Industrial Diesel Engine Service Repair Manual instruction book




Yanmar L48N L70N L100N Industrial Diesel Engine Workshop Service Repair Manual

This manual describes the service procedures for the LN series air-cooled, vertical single-cylinder, 4-stroke, direct injection engines. The use of this manual is recommended for safe, efficient and accurate servicing of the engine. Use this manual together with the current model specific parts catalog for additional exploded part diagrams and identification of part numbers. Parts catalogs are intended for part number identification only. Exploded part diagrams within parts catalogs should not be used as an assembly reference. Follow the assembly procedures within the correct service manual for proper assembly instructions. The information and procedures within this manual are for a typical engine. Some specifications and components may be different from your engine. All photographs and illustrations within this manual are intended as reference only and may not depict actual engine components or equipment. When servicing optional engine equipment, refer to the documentation supplied by that optional equipment manufacturer for specific service instructions. This manual may not include current field modifications or service updates that were not available at the time of printing.


  • Table  of  Contents iii
  • Introduction 1-
  • Yanmar Warranties 2-
  • Safety 3-
  • General  Service  Information 4-
  • Periodic  Maintenance 5-
  • Engine 6-
  • Fuel  System 7-
  • Starter 8-
  • Charging  System 9-
  • Electric Wiring 10-
  • Troubleshooting 11-

Yanmar L48N L70N L100N Industrial Diesel Engine Workshop Service Repair Manual