[sargentargent]

Had the same exact problem with a brand new engine. Idled perfectly but as soon as I attempted to rev the engine it would die. Disassembled the carb, cleaned it out with carb cleaner and blew it out with compressed air. No change. Went to my parts box and pulled out a new carb. Installed it and the engine ran fine. Try what the other guys said first. Then, if all fails, replace the carb. Make sure you have fresh fuel in the tank and that the fuel petcock (if so equipped) is turned on. Check or replace the fuel filter and fuel pump (if so equipped). You said it had been sitting for a long time. Did you put any fuel stabilizer in the tank before you let it sit? If not you'll have to drain the tank and maybe replace the fuel lines too.