You want to tighten the mixture screws until it starts to miss then open
them back up until it smooths out. Do not continue to open them after that.
While doing this you need to keep the idle speed at the rpm it should be.
In otherwords if adjusting the mixture speeds the rpm up back it down with
the idle speed adjustment. You want to adjust the mixture at idle. Very
few carbs have any adjustments besides idle mixture and speed. The rest of
the adjustments are made by changing jet sizes on just about all small
carbs. On multiple carbs you should readjust severals times going back and
forth between carbs. O multiple carbs it helps to have vacuum gauges ir
sticks.

wrote in message
ups.com...
My spark plugs keep getting quickly fouled with carbon residue, not
oil, I was told that too much fuel was getting into the cylinders and
not burning completly. I have scanned the Internet and can't seem to
find any "how to's" on properly adjusting idle and fuel mixture on a
small 4 stroke. Does anyone out there know??? A "helpful" man "helped"
me by claiming he could make my engine run better by making a few
carburetor adustments, since then, my plugs are fouled within 3 or 4
minutes running time.... yeah, thanks for the help....