You have not asked about your next problem. Fuel pump! The Tohatsu pump is on the carb, the Yamaha is not. You will need a pump, any external vacume style pump. The 70 Yamaha one is a good choice. You will need to tap a hole into the intake and install a threaded hose barb. 5/16 is good. You will need to install one in the back of the pump also and run a little hose from the intake to the pump.