Moped Engine Problems

Moped engines, simpler in design than four-stroke engines, can develop problems for numerous reasons.

Moped engines refer to two-stroke internal combustion engines that complete the process cycle during one revolution of the crankshaft. Moped engines, while low cost compared to four-stroke engines, can develop problems.

Spark Failure

Spark failure can cause a moped engine not to turn over, or start. Checking the spark plug consists of unscrewing it and inserting it between two cylinder heads so that the plug's outer ring comes into contact with the heads' cooling ribs. Activating the engine starter should turn the glow plug blue. If the plug produces little to no illumination, it should be replaced.

Carbon Deposits

Poor quality two-stroke oil can leave carbon deposits in the engine's exhaust port and pipe, resulting in engine power loss. Cleaning the exhaust port with a damp rag and using decarbonizing chemicals on the exhaust pipe typically corrects the problem.

Leaking Hoses

Leaking hoses in the engine system, which enable the fuel and air combustion mix to reach the engine, can allow too much air into the mix, resulting in irregular engine running. Any leaking or otherwise damaged hoses should be replaced to restore proper moped engine function.

References

• Gas Bike Shop: Moped Bicycle Engine Kit Installation
• "Two-Stroke Engine Repair and Maintenance"; Paul Dempsey; 2009

Resources

• "The High-Performance Two-Stroke Engine"; John C. Dixon; 2005