I´m having trouble with my DT175.. it starts OK but it will not go past 4K revs. I´ve cleaned the carb throughly and I´ve tried almost all carb settings (air etc), Changed the spark plug, checked and cleaned the fuel line, checked the reed valves (a little open but is starts alright)and I´m staring to fear a CDI problem... is there anyone out there who can give me some advice?? It would be much appreciated!