Question about the shift switch for evinrude????

[holstrom7171]

I have a 1969 thunderbird starflite that I just bought with an 85hp motor evinrude. where the throttle is the shift switch is no longer there. there is just 3 wires that are suppose to go to the switches. #1 ? is do these switches have to be working for the motor to start? I try to start the motor and the starter engages but does not turn the flywheel. #2 ? is there a way around there switches or can I use different switches to attach to the wires to make them work? Please help I am lost. thank you for your time.