I'd say it depends on what your generator is.
Mine is an Onan Marquis 5500 that runs at 1800 rpm, has a 3+ qt sump and a large oil filter. I run it alot (1500 hrs) and don't necessarily change the oil every year. It has never looked dirty (that's what the filter is for) but I do strive for the 150 hr change schedule.
path1 wrote:
Our generator in the last 12 months was only used when we "exercised" it. So maybe 20 hours total for year.
Manual says change oil every 150 hours or annually.
But I'm wondering what's the "mechanical" reason being so little hours.