2. Leaking fuel line: A damaged or loose fuel line can also allow fuel to leak into the oil pan. Inspect the fuel lines for any cracks.
3. Worn piston rings: As piston rings wear out, they can allow some fuel to get past them and enter the oil sump.
4. Sticking float valve: A sticking float valve can result in the carburetor flooding and fuel flowing into the engine's cylinders, eventually leaking past into the oil sump.
To properly check and determine the root cause, inspect those 4 points and make necessary replacement when applicable.
