Need Help

I just built my first motorized bike with the new 2010 80cc engine and I am having some trouble. At first it was working fine, i was only pulling the throttle about half way and going about 15 mph but the second time i took it out to ride it started spitting and popping, then as i would twist the throttle it would lose power, not accelerate, and sometimes stall. Ive tried adjusting the choke and idle screw on the carb but i dont know anything about how this idle screw works so i doubt that it helped any. Does any one have any thoughts about what could be causing this problem? The way my engine is sitting the carb is at about a 45 degree angle, could this contribute to the problem?

I forgot to say this in my original post but my bike wont idle either. i have to pull the clutch and keep the throttle pulled to keep it from stalling. Will this also be fixed by changing the angle and position of my motor/carb?

I mixed 11 oz of oil with 2 gallons of gas

mine is about the same but i think a little higher. I adjusted the angle of my engine,card durring my break from work today but do no have enough time to test it so ill will let everyone know if this adjustment worked later tonight once i ride it.