Modeled the Thermo Plate PN:318397 to facilitate producing a replacement. This retains the springs and valves in relation to the vernatherm. Part can be found in the exhaust drawings for 85693G Evinrude outboard engine.

I DO NOT recommend printing in materials with a melting temperature of less than 400 degrees F. An engineering buddy said the material was similar to Ultem in strength, density, and application.