Installation Instructions
18. Emission Control System
18-10 
Countermeasure for Emission Pollutants Not Within Standard as In Idle 
Speed (4-Stroke Engine) 
Note 1:  Test it according to the idling test procedure. 
Note 2:  Adjustment the idle adjustment screw.    Set the engine rpm in specified speed, and test CO, HC 
at idling.    And then adjust the air adjustment screw at the same time to let CO value to be 
1.5~4.5%. 
Note 3:  If the values still can not be reached to specification after adjusted the carburetor, then clean or 
replace it with new one according to the procedures. 
Conduct periodical inspection 
(check one time for 1500 km/6 
months) 
Test exhaust contents at idling 
(note 1) 
Adjustment carburetor (note 2)
Clean the carburetor   
(SJ, MJ, SAJ, MAJ) 
Replace the carburetor 
Keep the CO value in 
1.5~4.5% (note 3) by adjusting 
the carburetor. 
Clean the carbon deposit in 
cylinder and combustion 
chamber. 
Check piston rings for seized 
or leaking. 
Clean or replace the muffler. 
Inspect other related 
mechanism on the engine 
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