Dale, A few months back I cleaned the carb with an automotive parts cleaner/ dip and had it spotless inside and out. Cleaned all passages with compressed air and a guitar string until I was satisfied that it was clean. I found the throttle shaft worn along with the mixture shaft. I checked the pump last night and found it pumping on the last half of the stroke - half to full throttle when gradually applying throttle but when I firewall it fast, it works all-the-time. I thank the pump discharge check valve and/or the pump plunger assembly is the problem here. I know that I will need a new carb.because of the shaft play. The engine manual shows the Static Gravity fuel pres. at carb.--The C-85 carb uses 1/2 lb. and the O-200 carb. uses 2-6 lbs. As you know, a Cessna 150 has tanks in the wings which will produce more "head pressure" and the Baby tank is lower and produces less pressure. Would the C-85 carb. work on the O-200? "Steze" http://community.webtv.net/smlangford/StevesFlyBaby