@Cardinal (how the hell would rain water get in the sump!!!!!!)
Really easily if water gets into the air intake and you attempt to start the motor. The water gets sucked into the cylinder and then leaks past the rings into the sump. A common occurrence when yard machines are exposed to long term very heavy rain and they have a vertical air intake, such as those on some mowers where the air intake is on the handle to get away from dust.
Water taken in with a motor running does no harm – dissipates as steam immediately. It is often used to “de-coke” a cylinder. To do damage sufficient water has to get into the air cleaner to flood it and reach the carburetor. That usually takes a lot of rain, and usually a bit of wind. The vents are usually on the side, not the top.
It is something I have had considerable experience with, some of it very recently – in those huge storms we had a couple of weeks ago. Water damage to a mower and a wood chipper, but easily fixed.