Starts then runs full speed. tec 6.5 on toro personal pace

First I would check the carb and make sure the throttle plate has not come loose from the throttle shaft. If it has there is a small screw missing which should be retrieved if at all possible. Also check the springs on the throttle linkage to make sure they are not in a bind.
If the carb checks out and nothing is hung up then you can adjust the running speed by bending the tang that holds the fixed end of the throttle spring. bending towards the carb and loosening the spring will slow the motor and away from the carb/ stretching the spring will increase speed.
If you have slacked the spring and the motor continues to run fast then it needs a govenor adjustment.