Small Engines (Lawn Mowers, etc.): Carb Adjustments, carb adjustments, needle valves

Question
I have a 12 hp BS IC engine (281706-0203-01) that hasn't been run for two years.  I cleaned the carb and the engines starts easily but doesn't run well.  There are two needle valves, one on the bottom of the bowl and one on top of the carb.  What does each one do and what are good starting (from full in) for these adjustments?  Thanks.

Answer
Bob
The 2 needle valves are low speed and high speed.
Start at this setting close both valves till they bottom out "DO NOT OVER TIGHTEN THEM"Just enough to close them. Then turn each one at 3   1/2 turns out.Start the engine and at idle adjust the low idle first it should show you  which on is which usually on the bottom. One will be "L" the other will be "H" if you cant tell then the one on the bottom is low and the other high.
Adjust the low until the engine runs smooth at low idle then turn it just a 1/8 turn past. Do the same with the high speed but increase the throttle until it is high speed and adjust the same way.