Tohatsu 5 hp 4-stroke engine- max. 3000 rpm.

[Jarda]

Hello, I have a Tohatsu 5 hp 4-stroke engine, it starts well, and by the middle of the throttle it reaches about 3000 rpm. and further it is no longer possible to increase the speed, the engine suffocates and runs irregularly, as if there were a speed limiter. I replaced the ignition coil, candle, carburetor cleaned even by ultrasound. I no longer know how to identify and eliminate this defect ? Thank you for your reply.

 

[pvanv]

What does the plug look like? If dry, too lean if wet, flooding.