heres an interesting story about my new generator.
my generator has a 10hp tecumseh engine and a 5250w gen head. it is wired right to the mains on my house so that my entire house is powered. (the mains from the pole are disconnected now)
when i got the thing, the owner manual said to run it for an hour and change the oil, then its broken in. they made no reference to loads or anything.
i filled it with the oil that came with it (generic API SL 10w30), and started it up. i let it run for 5 mins under no load to warm up, and then switched on the house and gave the generator a real workout. i loaded that sucker down untill the 220v lines read 205 volts. that engine was bogging down to almost full throttle to maintain 3600rpm's. i did this for a period of 1 hour. after 1 hour, i changed the oil, which looked great. no metal flakes!
if you havent noticed, i broke the engine in by mototune's instructions.
the first tank of gas lasted only 6 hours, which was disappointing considering it has a 7 gallon tank.
the second tank, 9 hours.
third, 12 hours.
4th 13.5 hours.
5th, 13 hours
6th 14 hours
and so on.
it seems it took almost 35 hours of running for the engine to fully breakin and gain some efficency and lose some internal drag. after the 4th tank of gas, and 28 gallons later, all the subsiquent tanks of gas lasted for between 13 and 14 hours.
breaking the engine in by mototune's instructions yeilds no oil consumption over a 24 hour oil change period. the oil that drains out is only slightly darker than the fresh oil i put in it. the muffler has no soot, only BROWN discolouring on the inside. its not even black!
thats gotta be a first for a small aircooled engine. after 100 hours of running it i pulled the plug to have a look. the plug looked just as nice as my mums honda crv plugs. a nice tan colour, no soot, no blisters, the plug looked perfect.
the engine is usually running at about 50-70% throttle. if you apply this to mileage, like say a car driving at 75 mph for 24 hours, that would be around a 1600 mile oil change intrval, which i think is about right for a small aircooled flathead engine that has no oil pump, no filter, and a carburettor.
besides, at .6 quart capacity, it costs 43 cents a day to change the oil.
so there you have my expierence with breaking in a new generator.