Hold ON!!!!!! If you have the LATE style fuel pump eccentric it is in two parts and the outer ring will move a bit on the innner. That is NORMAL as it acts as a bearing surface.
Just for the record unless the fuel pump has a bad seal on the engine side it CANNOT put fuel into the engine
oil.
Most fuel in the
oil can be traced back to overly rich fuel mix or a choke not set correctly. That of course will cause the same thing. Really hard on the cylinders and rings.