I have a 1965 v4 90hp evinrude the motor never had a tach wired to it before. I want to put a tach on it so I wont over rmps the motor I bought a car tach and put on it but its not right. So a buddy of mine gave me a boat tach for points system which mine is. When i got to hook it up to the points side of the coil the motor will not run. can anyone help