Tohatsu carbs are identified not by venturi but by casting number. The 9.8 manual choke version is part number 3V2031003M, while the electric choke version is 3V2031333M. The 8 hp version has a MUCH smaller throat. The 8 hp manual choke version is part number 3V1031003M, while the electric choke version is 3V1031333M. You can call Tohatsu America at 469-771-3740 to check the casting number.