Coleman Power-Mate 5,000 Watt 6,250 Peak-Watts with 10 HP Tecumseh engine 3,600 RPM unit, and a Generac ix2000 Watt inverter type generator. GC (German Castrol 0W-30) in both. Beside keeping several quarts of GC handy, I do keep two quarts of Mobil 15W-50, and two quarts of Mobil 20W-50 V-twin, handy for use on days when the ambient temperature is > 90 Fahrenheit.