I have a John Deere LT 150 150B505432 with a kohler CV15S. 41618 engine that will not start. It has spark and the fuel pump has been replaced. New gas lines new gas filter changed the air filter. Cleaned out the gas tank. New gas gap. Gas lines and gas cap were changed because they were very sticky from the gas over the years. Carburetor was cleaned also. The gas is going to the carburetor and it cranks but will not start. It will not start with starting fluid either. What am I missing?