Just went through the same issue.
M 40 with oberdorfer n202m pump.
No water through the engine.
1. Changed impeller. Some improvement at 2000 rpms or higher no water
2.remove and clean heat exchanger. No help
3. Oberdorfer Repair kit for the pump, pressed new carbon bearing and seals. Nothing...
Have the same crack on 38-200, had it since purchase 5 years ago. Fiberglassed it 2 years ago, cracked again.
Assumed it was wet plywood, but will check the chainplate.
Just replaced all standing rigging, stripped and painted the mast on 38-200, headstay toggle was covered with a similar plate attached to the mast with 3 #10-32 screws.
Not a big deal, toggles are available from rigging only .com
Hey guys new Ericson 38-200 owner in Long Island NY. Looking for anyone in the area with Ericson 38 willing to show me the ropes, can crew on your boat or can pay for lessons on mine.