1st If the suspect fuel supply mixture is too thick, its phenomenon of the choke can not increase the speed of the engine. Then you can take off air filter, if this phenomenon is over, the engine can be sure the mixture is too thick. You should include the following elements:
â‘  observed choke is open;
â‘¡ float needle valve is not closed;
â‘¢ carburetor air is blocked;
â‘£ air filter is clogged;
⑤ main needle is too high.
2nd If the suspect engine to deliver a lean mixture, their appearance of the throttle valve, exhaust pipe sent guns, the engine temperature rises. Prevalent choke point if to overcome this phenomenon, that the engine too lean mixture. You should include the following elements:
â‘  fuel tank vent is blocked;
â‘¡ fuel tank switch is blocked;
â‘¢ carburetor is clogged;
â‘£ carburettor main needle position is too low;
⑤ float chamber oil level is too low.
3rd Idle should instability, four-stroke engines note check the following points:
â‘  throttle is used;
â‘¡ carburetor installation interfaces leaks
â‘¢ whether there is water in gasoline;
â‘£ idle setting is inappropriate.
For two-stroke engines, the following control elements have to be added:
â‘  crankshaft oil seal leaks
â‘¡ Flute Reed valve is damaged;
â‘¢ crankcase joint surface leaks.
4th Engine bad start, then check to observe the following points:
â‘  ignition system is defective;
â‘¡ engine compression ratio is less than the pressure;
â‘¢ fuel into the carburetor can