Small Engines (Lawn Mowers, etc.): snow blower carb, lean condition, speed circuit

Question
I have an ariens snowblower model 924026 serial #20931.last year everything worked well on it, the only problem i had was that if i would throttle it from slow to fast quickly it would hesitate and there would be black smoke but then it would run well at the fast position and would blow snow very well. this fall i decided to take the carb apart and clean out the carb with carb cleaner and put a new kit in. i set the adjustment needles to the factory settings(presets) and then tried blowing snow today but does not go well at all. it starts great, it throttles well, no hesitation or black smoke, but once i want to blow the snow the rev's go down and there is much less power compared to last year and does not blow the snow far. should i be doing "final adjustments" on the carb while the engine is running" or may something else be the problem?  

Answer
Bruce
The racing or hunting is caused by a lean condition. When you partially close the carb the air flow is reduced so that it don't run as lean try that.Then you know if it is the carburetor.Also it sounds like a restriction in the low speed circuit Try and adjust the settings according to what you hear as smoothing out sometimes you cant go buy factory setting they are mostly just a guide o get the engine started then you will have to adjust to your ear.