I have twin 350 mags in a 27 foot SR pachanga. Port engine, while running fine @ 4000K the temperature gauge gradually swings from 100 - 200 degrees every 15 - 30 seconds or so. exhaust plumes look even - no overheating sirens. At Idle speed it holds true at about 145. Does this sound familiar and is it symptomatic of a thermostat or a sending unit, or loose gauge wires? It does not run hot and stay there, or go too cool and stay there. Always moving up and down at higher RPM.
