Small Engines (Lawn Mowers, etc.): Kohler engine problems, ring gasket, fuel tank cap

Question
I have a 22 HP  Koler engine that was a brand new engine last year. We serviced the machine and just changed the oil and replaced the plugs. It was running fine. We started the blades and then it lost power and began to run poorly. We can get it started but only by choking it and leaving the choke on. It will run a short time and then stop. The engine is on a Bobcat Zero turn mower model # 942212 The Kohler engine number is
CV22S. We tried  changing the carb from the old engine we had and  the engine ran the same. We are stumped.

Answer
Clyde

Possible causes:

  1. Fuel tank is empty or shutoff valve is closed, or fuel line or fuel tank cap vent is clogged.
  2. Carburetor is over choked.
  3. Carburetor is improperly adjusted or needs service.
  4.Carburetor is dirty.
  5.Air leak in carburetor or intake manifold (e.g., bad O-ring, gasket, primer).
  6 Old gas, bad spark plug, very thick/dirty oil.
  7 Ignition not timed correctly.
  8 Air filter is clogged.
  9 There is a lack of lubrication.
  10 Valves are not sealing properly.
  11 Piston rings are not sealing properly.
  12 Head loose or head gasket blown or damaged.