I don't think the Honda manual for any generator calls for 25 hour oil changes. Mine says 100 hours. But let's think this through - we are dealing with a low-stressed motor, running at constant speed. It's like changing a car oil at 1,000 miles or less. I advocate a quick break-in change, but after that, you need to go at least 50 hours. 25 hours is not connected to reality.