We have a 1982 E38. Universal 3452 w/ 3,800 hours. We're cruising in Mexico. Water temps 75 degrees. At 1,700 RPM, engine will hold temp at 185 degrees (all temps measured with gun just top of thermostat). Rev. up to 2,100 and over a 5 to 8 minute period it climbs to ~210. Throttle back to 1,700...