After priming using the bulb the mower runs about 2 seconds. After a reprime its starts and run again for about 2 seconds. I have disassembled the carburator several times in the pass three years. At first this got me through the season. Now its seems to work only for a few days. There are two hoses connected to the carburator. One is the fuel supply. Could someone tell me the purpose of the other hose?