I have a 1979 7.5hp gamefisher motor. model#217-585931, motor#640-18A(Tecumseh).My problem is the motor runs fine at idle,and mid-throttle.Once you open the trottle wide open it will run fine for about 5 seconds then just bog down and cut off as if it is starving for fuel.Could it be the little rubber fuel pump in the carb. flange?Any advice would be greatly appreciated. 