Hi all,
I'm scratching my head trying to figure out the cause/source of a leak. After running my MC21 and leaving for a few days I end up with quite a lot of petrol mixed with some oil on the left expansion chamber, inside the generator cover and dripping down from the gear selector shaft. Initially I thought I had a crank case leak. But it is sealing well after doing as pressure check.
I know my fuel cock is leaky (in the OFF position is still fills the carbs after a few hours). I previously have had issues with carb float needle not sealing and filling the chamber.

What I cannot figure out is why the fuel is leaking over the engine? Would it be flowing out the carb overflow? On inspection the area beneath the carb overflow looks spotlessly clean. The fuel line, tank and all the obvious sources all appear fine.

Also, why would there be oil mixed with the fuel?