Sounds like the fuel is not getting through the carb in sufficient amount. So you're limiting the air to correct the ratio with your fingers, as opposed to using the choke. The choke doesn't work? Carb cleaner is your friend, use it liberally on all the jet openings and especially on the main needle and seat. Make sure the carb is all the way on the intake, think air leak. I found the manual for QT-50's online for free, using google. I literally just spent the day going thru the rear brakes and carb. on my $20 QT-50. I'll get back to you on the float setting. Where in K.C. are you? I'm about 50 miles south of K.C.