Small Engines (Lawn Mowers, etc.): Mikuni carburetor, inch diameter hole, inch holes

Question
Hi,
I am working on a Mikunit Kogyo carburetor on a 2 cycle Robin EC10 engine.  It idles ok, but when I increase throttle, the engine bogs down.  I think the mixture could be set wrong. I don't know which screws correspond to what operation. There is one screw with a tiny, I would estimate 0.010 inch diameter hole drilled up the axis, with three .050 inch holes drill perpendicular to the axis at different locations on the perimeter.  What is that for?  What are the basic steps to adjusting a carb?  Thanks  

Answer
The starting point I like to use for the mixture screws is 1 1/2 turns out from lightly seated (low & high speed). The low speed is closest to the cylinder and the high speed is right beside it. The idle adjustment screw is not in the same proximity of the mixture screws. I like to set the high speed first. Hold the throttle wide open and begin turning the high speed screw in until the engine revs as high as it will go (this is too lean and don't do it for too long), then back it out 1/4 of turn (mixture will be sufficiently rich to provide power at high RPM). With the engine idling (you may have to adjust the idle screw slightly so it will idle somewhat normally), open the throttle rapidly. There should be no hesitation. Turn the low speed mixture in 1/8 of a turn and open the throttle rapidly. If there is still no hesitation, turn the low speed in another 1/8 of a turn. Keep doing this until you find that it hesitates, then back it out 1/4 of a turn. This will be sufficiently rich to provide power off-idle. Then you can fine tune your idle. Hope this helps.