i can allmost guarantee you that your carb needs rebuilding,,,,,,sometimes the reeds get warped just sitting up also,,then there is the possibility you may have an air leak on your case seal,,ive found them by pressurizing the case and using soapy water,,,its been my experience that the rubber parts will either petrify or not seal if left out of service for a month or two....thats in the carb or reed block..oh i forgot to add ,,if you live in or near any decent sized town,,most lawnmower shops will have the kit to rebuild,,,and in the kit will be several different gaskets and rubber parts,,,just use the ones that exactly match the ones in tour carb,,just be extra careful if you change the metering needle,foung attached to the little fork under the diaphragm,its about the tuochiest part of the job..