bigted may have missed your post roebuck, so I'll give you an answer. If you get a fair amount of liquid - usually water or petrol - in an engine's cylinder, because liquids are incompressible, the engine cannot rotate to top dead center. This is commonly called "hydraulic lock" or just having "hydraulicked" the engine. Sometimes people do dumb things after it happens. I can remember three nasty incidents involving car engines. In the first instance, an amateur borrowed a very old FC Holden wagon and decided as an unrequested favour to the owner, he would decarbonise the cylinder head. He didn't do a very good job of reinstalling the cylinder head (re-using the old gasket), and cooling water filled one cylinder. Not recognising the signs, he tried very hard to rotate the engine, then gave it back to the owner. The owner found it was hydraulicked, and removed the sump to take a look. Sure enough, the center main bearing cap was laying on the sump: he'd broken both of the bearing cap bolts in his attempts to rotate it. In the second case, some experimenters were trying to fit a Bosch K Jetronic fuel injection system to a Holden V8. Due to them not bleeding the system before they powered it up, it injected fuel continuously, and hydraulicked a couple of cylinders. A slightly wiser mechanic was passing by at the time and told them what they'd done wrong, so they removed the spark plugs and spun up the engine on the starter to eject the petrol from the cylinders. Unfortunately they had not disconnected the low tension side of the ignition, so the loose plug leads were sparking to ground when they spun it, and a good sized fire resulted. In the third case, a fellow went bush with a brand shiny new diesel 4WD. He encouraged a friend to drive it through a river. Unfortunately the friend was inexperienced and allowed the car to drift sideways off the ford, so it dropped into 4 feet of water, and sucked in an engine full of the stuff. Undeterred the fellow bribed a local farmer to tow the 4WD out of the river, then found the engine would not crank on the starter. So of course he had it towed along the road with another 4WD, repeatedly banging the clutch trying to get the engine to rotate. When all that failed he had it taken back to the manufacturer on a flat-bed and claimed warranty. His claim was unsuccessful, and the manufacturer replaced the crankshaft and all of the rods and pistons.
After that graphic description, you'll probably remember what a hydraulic lock is. It happens from time to time to mower engines with gravity fuel feed, when somebody leaves the fuel tap on and the needle and seat leaks.
