hi. i recently purchased my first boat. its a 14ft aluminum with a 1975 20hp merc 200. the motor ran awesome here at the house. a couple of weeks ago i took it to the lake to try it out and i started having problems. first off, it had trouble starting. then when i got it started, it wouldnt stay running. it only runs for a few seconds after i prime it. so obviously its a fuel issue. i bought a new fuel pump diaphragm for it and that didnt fix it. im thinking something may be plugged in the carburetor maybe? i have a clymers manual and im thinking i may just disassemble it and clean every little orrifice. any other ideas? thank you