Not usually
There should be 4 basic wires connecting the mower to the engine.
1) kill wire - with the brake on & PTO off should go from ground to open when you turn the key from off to on
2) carb solenoid wire - should go from open to battery voltage when key goes from off to on
3) Power wire from rectifier - usually red should show voltage when engine is running
4) starter solenoid wire, generally purple on Kohlers, goes to the trigger wire on the starter solenoid
So follow the unknown wires on the engine side & see whee they go to .