| phenomenon | analysis | problem cause |
• low speed • low output | • choke closed | • open the choke |
| • muffler blocked | • clean or change the muffler |
| • parts worn away | • change |
| • ignition energy low | • change the igniter or flywheel |
| • ignition timing not correct | • adjust the timing |
| • valve gap too big | • adjust or change the parts |
| • carbon deposition in cylinder head | • clean |
| • wrong assembly of carburetor insulation gasket | • re-assemble |
• hunting | • oil-away blocked,too thick or too thin | • adjust |
| • spark plug gap too big or small | • adjust |
| • abnormal knocking | • wrong valve ga | • chang |
| • camshaft tooth damaged | • change the driving tooth or governor gear |
| • carburetor leakage | • needle valve not fully closed | • clean or change |
| • sealing parts damaged | • change |
| • umbrella-shaped valve not fully closed or damaged | • clean or change |
