You will get normal carbon deposits in the engine, they are a product of combustion and this one of the disadvantages of the two-stroke engine, that it does not burn as completely as the four stroke engine does. Anyway, how much carbon are you talking about? A thin hard layer or goopy gross masses of it. If it's the latter, you probably are running rich and if so you'll be noticing greater amounts than normal of smoke from your silencer and you should be fouling plugs. What are your plugs looking like? Black and wet with the same deposits on them? If so you're looking at a rich condition. Post back.