| phenomenon | analysis | solution |
| weak | spark plug | • spark plug fouled | • clean the fouling |
| or | • the gap is too big or too small | • adjust the gap to 0.6～0.7mm |
| no spark | • the insulation damaged | • change the spark plug |
| igniter | • igniter damaged, weak magnetic in the flywheel | • change the igniter or flywheel |
| • gap between igniter and flywheel is too big | • adjust the gap to 0.3～0.5mm |
| others | • poor contact between the high voltage wire and the spark plug | • re-connect |
| • engine stop switch failure or short circuit | • change |
| spark jumps | correct compression | • too much fuel in cylinder | • clean the spark plu |
| • low quality fuel | • change the fuel • clean the filter |
| • high resistance in the air filter |
|
| correct fuel feed, abnormal compression | • worn piston ring | • chang |
| • spark plug loose | • fasten |
| • cylinder head leakage, abnormal valve timing | • adjust or change |
| carburetor pump fuel or not | • fuel tube damaged,blocked,the diaphragm and the valve damage | • clean or change the carburetor |
