200,
How high is the motor jacked? Sounds like the water inlets may be a little high, you didn’t tell us it was raised above normal. those blistered plugs spell trouble still!
I don’t think that was the issue. The ventilation plate was lined up with the bottom of the boat or slightly lower; and as I wrote, the hot running condition was reproduced both on and off the boat (using a test wheel in my big test tank).
