J70ELCSA, 1980 70hp, I have water in #2 and #3 cyls.
Just went thru all the other repairs (carb kits, fuel lines, plugs, thermostat, etc.) and finally started up in water.
Pees good. No overheating.
Compression 120 across all three. Spark good across 7/16 air gap.
Then I pulled the new plugs...