I bought a 1990 23' Grady White with a 1990 Yamaha 250 XP 76 degree outboard motor. It sat for four years prior to my purchase. The motor wasn't running and has been completely cleaned out. All of the fuel filters, pumps, electrical have been replaced. The fuel was siphoned and the tanks cleaned. The boat now runs at idle speed or full throttle, nothing in between. As soon as you let up on the throttle, it stalls out. It will start back up, but the same thing will happen. Any suggestions out there?
