i have an old sears tecumseh on a manco mini bike, and it wont run right. it starts and idles fine but when i give it gas it wants to go at first, but then it cuts out and sputters and caughs and has power surges on and off. it acts like its running out of gas! but its getting plenty of gas and i totaly cleaned out carb like 4 times and replaced everything like needle and seat and diaphram and it shouldnt have any leaks, but its acting like its not sucking enough gas! plz hepl its a 3.5 hp sears tecumseh with a diaphram carb and i think its like an h22 or h35. and the number says 143 784112 im thinking of buying a new carb for it, but i hate to pay 60 bucks and have it do the same thing. cuz it dont look like anything is wrong with the carb. it looks fine but it sure acts like its a carb problem!