Shandong Huasheng Zhongtian Machinery Group Co., Ltd. Shandong Huasheng Zhongtian Engineering Machinery Co., Ltd.
10
3. Repair
Instructions
3.1
Importance of Correct Operation
Correct maintenance is a key to ensure the users safety and the proper performance of gasoline
engine. Any technological error or negligence in the process of repairing will impair the gasoline
engine or cause physical harm to users.
3.2
Notices for Repair
1. It is required to use original parts and lubricant or specified products.
2. It is required to use special tools for operation requiring special tools.
3. It is required to replace with new washers, gaskets and O-rings as long as the gasoline
engine is dismantled.
4. In fastening bolts, nuts and screws, it is required to screw to specified torque (except for
cases with special regulations) in sequence of “from big to small diameter, from inside to
outside” and in diagonal line.
5. It is required to clean parts after they are removed and apply the engine oil on the rotation
surface in the process of installation.
6. It is required to check the conditions of rotation and movement of each part after the
assembly is completed.
7. Only metric tool can be used in repairing the gasoline engine. Improper use of tool may
damage gasoline engine.
3.3
Standards for Repair
Item
Limit value for repair
1
Cylinder inner bore
43.6
2
Clearance between the piston and the cylinder
0.15
3
Clearance between the piston ring and the ring groove
0.17
4
Clearance of the piston ring gap
0.2-0.5
5
Clearance between the piston and the piston ring stopping pin
0.1
6
Big end lateral clearance
0.5
7
Clearance between the piston and the piston pin hole
0.06
8
Crankshaft main bearing journal diameter
17.02
3.4
Torque Value
Torque value
Fastening parts
Specification of
fastening parts
N·m Kgf·m
Cylinder fixing screw
M5
7
～
9 0.7
～
0.9
Starter locking bolt
M4
1
～
2 0.1
～
0.2
