Small Engines (Lawn Mowers, etc.): Kohler motor wont keep running, kohler engine, adjustment screws

Question
We have a 26 hp Craftsman mower, Model 917-275900, with a Kohler engine, model CV 730S, Spec No. CV730-0043.  A while back it would not start.  It would start and run if you pour gas in the carb, but cuts off as soon as the gas is gone.  We have installed carb kit and cleaned carb -- it was really gunky.  No change.  We have replaced spark plug, fuel filter, solenoid, accelerator pump kit, fuel pump.  Same thing.  Engine will run if gas is poured into the carb until the gas is gone.  Will also run if carb clearner is sprayed into carb in short bursts to keep it running.  Also, we had 2 gaskets between the carb and intake -- is that proper or an assembly error?  Can you tell us where the adjustment screws are located?  Thanks for your help.

Answer
does the engine have back fire suppression on it?  To tell look at the bolt that holds the carburetor bowl on.  Is there a wire or two coming out the bottom of it?  If there is it may be the cause.  This system shuts off the gas as soon as the ignition is stopped.  To tell if this is it. Remove the bolt and remove the needle and spring.  If gas flows replace the system with a new one.  

If this is not the case remove the carburetor and disassemble it completely.  Take the nozzle out of it too.  It is the brass piece that screws into the center of the carb and goes up into the venturi.  Use a wire from a twist tie and clean all passages, fuel and air. Reassemble the carb and install.  Before installing the fuel lines because you have fuel flow to the carb.   If you have to remove the fuel cap to make it flow replace the fuel cap.  Check the fuel filter.  Just the choke and throttle cables. Check the pulse lines from the crankcase to the fuel pump.  

If this is not it.  Remove the engine and fuel tank and inspect the system.  Fuel should flow freely from the tank to the engine.  If it won't the issue is in the tank and lines.  If fuel will flow to the engine the issue is in the fuel system in the engine.  Isolate the problem area.  I don't think this tractor has and electric fuel ump on it.  If fuel is in the carb then there is something keeping it from getting from the carb bowl to the combustion chamber.  Have you checked intake valve clearance? Get back to me with what you find.