My quad has been smoking quite a bit since i have rebuilt my carb so i have taken my plug out and found that it has a thick black layer all over it, ive got a new spark plug so i can start again, i just need to no how to correct this problem ?

 

Sounds like something is either put together wrong, or out of adjustment with the carb. Or the air filter is very dirty or overoiled with the wrong type of oil.
Once the jetting is right...the spark plug will be ok. The spark plug is just the symptom,..not the problem.

 

yeh i guess its to do with the fuel/air screw, i forgot to count the amount of turns when i unscrewed it so that must be the problem. i dont no whether this adds to it but there is alot of full coming out of the fuel bowl, the drainage screw it tight, the float isnt damaged and it is not sticking. i may aswel get a replacement jetting kit.

 

Smoking? Let's first determine what color smoke. Can I assume you mean black smoke? White/Blue smoke is a different problem.

 

If fuel is coming out of the overflow tube on the bottom of the float bowl...then thats the problem. The floats are sticking, or it was assembled wrong..but whatever, the high fuel level in the carb is causing the rich condition. When you find out why the float, or needle and seat are apart, and fix it...the over rich condition will go away.
The mixture screw will only effect idle mixture...once you open the throttle, the other circuits take over. But if the needle and seat, are open all the time, and the float bowl is too full....all circuits will be too rich.
I dont think you need a rebuild kit..just take it apart, and see why the needle and seat are staying apart.

 

ok cheers.