here is mine with the old carb i sealed up with permetex , also in the manual it shows 2 o rings on the base of the carb, hope this helps.
the second pic i put permetex around the valve , then sealed up the bolt that holds it to the motor.
try this setting the needles, first set the low end or low speed needle , get it to idle and when you give it throttle it dosent stall , set the idle stop to about a penny width first so when the throttle is closed you only see about the width of a penny opening. then set the high speed needle you will be surprised how much you need to richen the low speed compared to the high speed needle. high pitch wine usually means its lean , check these videos out
http://www.youtube.com/watch?v=prX0OeQLrbw