Anyone out there got ideas/drawings for a very simple steering mechanism for a model go kart?

Answer 1

Are you wanting a mechanism that will turn the wheels when you turn the steering wheel or one that will steer the car remotely by a wire or RC?
The former is most easily done with a flat bar steering arm soldered in an L position on the end of the steering wheel shaft (or held with set screws or pinned in a larger version) and the end of flat has a hole. The front wheel are mounted on pivots with an arm at right angles to the pivot axis which also has holes. A wire is bent with crank ends to fit in the holes to connect the steering arm to one of the wheels and another is bent to connect the right wheel to the left. The wire between the wheels is put in first, bent to fit when both wheels are straight. The wire from steering arm is put in next with the arm pointing down (or up but centered) and the wheels centered.
On larger models tubing is used instead of wire and threaded fittings can allow adjustment.