If you live in the Desert SouthWest, moisture is not requiring oil changed so often. Moondust is Your particular enemy: that flour-fine dust that is everywhere.
So, I would change Synthetic oil only Once a Year, right after the Once every Six Month's 50% Loaded, Half Hour runs. Air Filter service once a Year.
Store Zero fuel in the Generators, and shut off fuel after unloading the genset and allowing Ten Minutes,@minimum, Cooldown run. Running till completely out of Fuel. When dead cold, remove sparkplug and shoot a squirt of Marvel Mystery Motor Oil, and crank a few times, then using anti-Seize, replace plug with correct torque. (If you want to be completely OCD about it, use NEW sparkplug washer.) Finally, before storing, select Choke ON, as it closes off the intake passages into the Motor.
Then, to combat the moondust, completely enclose the Genset in a plastic Garbage bag. Tie or knot the bag shut, after tossing a couple camphor balls and/or cedar shavings(in a net bag) - keeps spiders, scorpions and rats from gen windings, fuel lines, and wires. The moondust is abrasive and insulating, both properties anathema to longevity.
I am also particular to Iridium (Platinum in a pinch)sparkplugs, as they don't erode anywhere as fast during long, hot runs. Further, they have a teensy area center electrode, concentrating the spark blast, thus burning off any fouling and reaching through any flooding as well. Aids in
[email protected] pull. Pay attention to correct Heat Range, selecting exact or One step Cooler, as the arc concentration will compensate, and one range cooler helps at heavy loading.
Mobil 1 oil is absolute best, and since the oil sumps of these portable gensets are so small, the price differential is negligeable. Changing once every other or once every Three Years seems reasonable, but for me, was it last Year? Two years ago?...For me, Once every Year in Early Autumn, is no muss, no fuss, peace of mind.
If K&N makes an Air filter element for Your Gensets, buy Two per motor! In the absence of K&N, look into the OEM filter oiling procedure, and maybe add a prefilter sock of oiled sponge or cloth, as is done for Desert Motorsports' engines. Stop the moondust!