Make sure you have a good gas to oil mixture, My 25cc 1999, is 50:1, Be sure you're not sucking air from faulty fuel lines or fuel line connections. Make sure the air filter is clean, and oiled if it requires oil. Turn your idle screw in till it stops, then start at 1 1/4 turns out, and then an 1/8 of a turn at a time if all else has been checked and is well... You will adjust the idle screw till you can Idle without giving it gas, (after the engine is warm)... If you have a high air/fuel mixture screw, screw it in until it stops.(Do not over tighten). Screw out 1 1/4 turns... Adjust these two screws 1/8 of a turn at a time until there is power all the way through the RPM range. Oh... And check your plug... if it is wet or black and sooty , then clean or replace it, it should be a golden brown with no soot.
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Make sure you have a good gas to oil mixture, My 25cc 1999, is 50:1, Be sure you're not sucking air from faulty fuel lines or fuel line connections. Make sure the air filter is clean, and oiled if it requires oil. Turn your idle screw in till it stops, then start at 1 1/4 turns out, and then an 1/8 of a turn at a time if all else has been checked and is well... You will adjust the idle screw till you can Idle without giving it gas, (after the engine is warm)... If you have a high air/fuel mixture screw, screw it in until it stops.(Do not over tighten). Screw out 1 1/4 turns... Adjust these two screws 1/8 of a turn at a time until there is power all the way through the RPM range. Oh... And check your plug... if it is wet or black and sooty , then clean or replace it, it should be a golden brown with no soot.