Yea spinning it with comp release engaged will allow the pistons to spin freely and push all the excess fuel out harmlessly is this was the case.
My needle on my lawmower got gelled up while i was cutting. I put more fuel in it cause i thought this was the problem and when i got back to the mower i had fuel leaking out of the carb air cleaner. It was flooded but there is a drain in the air filter so that they usually dont hydro lock. It was really flooded bit i got it turned over after i disasembled the carb and pulled the needle and got the goo off of it??? Darn ethonol fuel!
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In the case with my mower after thinking the battery was low I put the charger on it, it didn't help, so the next thing was to pull the spark plug, as I removed the plug gas started flowing from the plug hole, Wow! I then tried turning it over again, even though it did spin over faster something just didn't seem right with the way it sound, I notice the gas tank was empty, and it certainly didn't run out setting there,
Oh but it did! run out into the engines crankcase, I pulled the dipstick and it was way way above normal level, Next I spun off the oil filter and oil/gas flowed out and smelled more like gas than oil, then I drain the crankcase, did a quick research on why this could happen,
was the ( fuel shutoff solenoid ) replaced it and fired right up,
Not to get this confused with the OP problem,
but in reply to a lawn mower engine block can in fact be filled with fuel,
This type mower ( Craftsman )were built throughout the late 90's, when the fuel solenoid shut offs were first being used, along with elevated fuel tanks, could allow fuel to flow by gravity, should have put a shut-off at the tank, evidently this was an ongoing problem which result in the new design, By relocating and lowering the fuel tanks and installing fuel pumps, Now an engine must be started in order to pump fuel into the carburetor,