1. K15/21/25 Gasoline Engine
Service Manual #

2. The following modules do not cover all of the material in the manual
The following modules do not cover all of the material in the manual. We have identified and chosen some of the more important key points. To fully understand the engine in more depth you will need to read the manual. More hands on work with the lift truck, and real life work will improve your overall knowledge of this equipment.

3. Introduction

4. Engine Models and Fuel Type
Engine Type
Engine Control System
K15
Carburetor Specification (Gas/LPG)
Electronic Controlled (Gas/LPG)
K21
K25

5. External View (Carburetor type)

6. External View (Electronic Type)

7. Indication of Model and Number

8. K15 Engine Specification

9. K15 Engine Specification

10. K21 Engine Specification

11. K21 Engine Specification

12. K25 Engine Specification

13. K25 Engine Specification

14. Engine Main Parts

15. Cylinder Heads & Valve Mechanism

16. Cylinder Head Cylinder head is common with K15, k21and K25
Made of aluminum alloy material

17. Rocker Cover Removal of rocker cover and gasket:
1. Remove the rocker cover retaining nuts.
2. Remove rocker cover.

18. Rocker Shaft Assembly Removal of rocker shaft assembly.
Loosen the eight valve rocket adjusting nuts and screws to remove the valve rocker shaft.
Pull off the push rod.
When removing the valve rocker shaft, compress the coil spring slightly and tie the spring with a metal wire, as shown in the figure, before loosening the bolts. This will facilitate the reassembly work later.

19. Assemble Cylinder Head
Retighten the bolts in the sequence shown in the figure while the engine is cold.
Torque: 68.6 N-m (7.0kgf·m)

20. Assemble Rocker Shaft Assembly
Tighten the rocker shaft retaining bolts evenly from inside to outside
Torque: – N-m (1.8 – 2.2kgf·m)

21. Adjusting Valve Clearance
1. Start the engine and fully warm it up. Then stop engine.
2. Remove rocker cover
3. Turn crankshaft – Set piston for No. 1 cylinder to the compression TDC and adjust valve clearance for (1) (2) (3) (5) in step 1.
4. Set piston fro No. 4 cylinder to the compression TDC and adjust valve clearance for (4) (6) (7) (8) in step 2.
Adjust Valve Clearance when Engine is Hot

22. Adjusting Valve Clearance
Intake and Exhaust: 0.38 mm
Adjust Valve Clearance when Engine is Hot

23. Pistons, Crankshaft & Crankcase

24. PTO Device

25. Piston And Connecting Rod
The front of the connecting rod is determined as follow:
When installed to the piston and view from the front, the projection should come to the right.

26. Assembly of Piston Ring
1. Securely assemble the top ring, second ring and oil ring to their relevant positions.
2. Make sure to assemble these parts in the following order: oil ring, second ring, top ring.

27. Assembly of Camshaft
1. Gently put the camshaft into the camshaft hole so that the bearing bushings are no damaged.
2. Tighten locating plate to the specified torque – 10.8 Nm (0.86 – 1.1 kgf.m)

28. Assembly of Timing chain/Sprocket
Tighten camshaft bolts. Tightening torque: 39.2 – 49 Nm (4.0 – 5.0 kgf.m)

29. Assembly of Timing chain/Sprocket
Check the height of the cam shaft gear and crankshaft gear end faces, adjust the height by adding shims to the crankshaft side as necessary.

30. Assembly of Timing chain/Sprocket
Assemble chain tensioner.
When installing the chain tensioner, align the oil holes of the tensioner body to those of the cylinder block to ensure that the tensioner spindle shoe (synthetic rubber) is held parallel with the chain.
CAUTION: Assemble shoe correctly

31. Installation of Crankshaft Pulley
Set the crankshaft pulley by aligning the pulley claws to the groove of the bushing.

32. Inlet and Exhaust System

33. Inlet and Exhaust

34. Cooling System

35. Coolant Block Diagram

36. Water Pump, Fan & Thermostat

37. Engine Coolant Sensor & Transmitter

38. Remove Water Pump
1. Open the drain of the radiator and extract coolant.
2. Remove the radiator shroud.
3. Loosen the alternator adjusting bolt.
4. Fully put aside the alternator toward the engine.
5. Remove fan and fan pulley
6. Remove water pump together with the gasket.

39. Water Pump Inspection Do not disassemble water pump
Check the water pump vanes for rust and pitching.
Do not disassemble water pump

40. Water Pump Inspection Do not disassemble water pump
Check the water pump bearing for proper end play and smooth operation.
Do not disassemble water pump

41. Fan Belt Tension
Belt Deflection: 11 – 13 mm
Force: 98 N (10 kgf)

42. Fuel System

43. Fuel System Diagram

44. Fuel Pump & Fuel Filter
Periodically inspect, clean and replace fuel filter.
Clean fuel filter every 3 months.

45. Vacuum Piping Diagram

46. Carburetor and Governor

47. Carburetor Assembly

48. Spark Plug Gap
Standard (mm) : 9

49. Lubrication System

50. Engine oil Lubricating system

51. Engine oil Lubricating Flowchart

52. Oil Filter

53. Oil Pump
Oil Pressure
At idle, 98 kPa (1.0 kgf/cm2)
At 2000 rpm, kPa
( kgf/cm2)
No service parts. Replace drive shaft assembly or oil pump assembly

54. Engine Inspection & Adjustment

55. Engine Speed Measurement
1. Remove the distribution connector from the coupling as shown.

56. Engine Speed Measurement
2. Connect the ignition coil adapter harness between the distributor connector and coupling. Connect the tachometer power supply terminal (red) to the battery positive terminal and the black terminal to the battery negative terminal. Connect the measurement terminal (green) to the measurement wire in the middle of the adapter harness

57. Engine Speed Adjustment
1. Start and warm up engine sufficiently.
2. Check that FICD (fast idle control device) does not contact the carburetor throttle lever.
3. Adjust the idle speed by using the throttle adjusting screw and idling adjusting screw. Idle speed :700 ± 50 rpm
Caution: The idling and maximum speed are preset at factory. Do not adjust unless necessary.

58. Engine Speed Adjustment
4. Adjust the ignition timing for idling.
Ignition timing: BTDC:
K15 : 0o
K21 : 2o
K25 : 0o
Caution: The idling and maximum speed are preset at factory. Do not adjust unless necessary.

59. Engine Speed Adjustment
6. Remove the vacuum piping from FICD and plug the pipe openings to prevent air leakage.
7. In this state, the FICD pushrod is pushing the carburetor throttle lever. Adjust engine speed to 1200 – 1500 rpm with the throttle lever adjusting screw.
8. After adjustment, connect the vacuum piping and verify that an appropriate engine idle speed is obtained.
Caution: The idling and maximum speed are preset at factory. Do not adjust unless necessary.

60. Governor Adjustment (No Load)
1. Set the directional lever to neutral position.
2. Start engine and fully open the throttle. Monitor the engine speed.
Maximum speed with no load
K15 : 3,600 rpm
K21 : 3,600 rpm
K25 : 3,600 rpm
3. If the engine speed does not fall in the specified range, adjust by turning the governor adjusting handle.
Caution: The governor is preset at factory. Do not adjust unless necessary.

61. Governor Adjustment (With Load)
1. Set the directional lever to neutral position.
2. Start engine and fully tilt the mast rearward with the tile lever.
3. Fully open the throttle and monitor the engine speed.
Maximum speed with load
K15 : 3,000 rpm
K21 : 3,000 rpm
K25 : 3,000 rpm
4. If the engine speed does not fall in the specified range, adjust by turning the governor adjusting handle. In addition, adjust the maximum engine speed with no load.
Caution: The governor is preset at factory. Do not adjust unless necessary.

62. Testing Compression Pressure
1. Warn up engine and then stop.
2. Remove the spark plug.
3. Connect compression gauge correctly to the cylinder plug hole to be measure.
4. Set throttle valve to the fully open position. Depress the throttle pedal to the fully open-open position.
5. Crank the engine and read gauge.
Unit: MPa (kgf/cm2)
K15
1.27 (13.0), 250 rpm
K21
1.23 (12.5), 250 rpm
K25
Note: Keep engine speed at approx. 250 rpm
Take reading in a short time as possible

63. Maintenance Schedule

64. Maintenance Schedule