This owner was the lucky recipient of an engine hydrolock event while under sail. When he went to start the engine a cylinder was filled with water, and water is in-compressible.
"But RC it worked for 6 years with no issues."
Another way to look at that:
"You got lucky for 6 years."
Yes, a professional boatyard did this installation... Apparently no one informed them that when sailing with a "scoop strainer" water can be forced up and over the siphon break, into the water lift muffler and can eventually back fill a cylinder. Raw water pumps are not shut off valves and they do and can leak water by. Facing a scoop strainer forward is an incorrect installation for a sailboat. Heck directional scoop strainers should not even be used on sailboats..