Two reasons for fuel in oil, one, the fuel pressure overcomes the float and floods the engine, or two, the fuel pump is bad again. Carb should be easy to see, it will be running terrible. This leaves the fuel pump.
To test this, a electric fuel pump could be installed bypassing the mechanical. With a regulator set to 2.5 psi, you should be able to run your tests. If you gain no oil level, then the fuel pump was the problem.
Its not really that hard to believe you keep getting junk fuel pumps. I suspect the fuel in your area maybe eating them up. Take it apart and see where it's leaking from, that might give you a idea where to go next.
Joe
