I found some oil residue in certain areas of my generator which I believe was caused by overfilling. First, there was oil coming out of the oil level grommet were it enters the block. This was causing oil to drip on the bottom tray (about 1/2 teaspoon in 10 hrs). Second, I found an unusual amount of oil in the foam air filter and box that dripped down on the bottom tray (very small amount). I could tell the oil had been coming out of the carburetor (?). Third, there were some oil droplets on the cover grille were the stator airstream exits (below the muffler).
My generator is new and has 375 hrs run time; overfilling occurred at the 20, 100 and 200 oil changes. I was adding oil to just about the middle of the threads in the filling tube instead of the first thread. I've since added the correct amount of oil and there is no more residue on the above mentioned areas.
Is the oil found a result of the overfilling? Can this result in equipment damage? Any further / deeper cleaning I should perform?
What you describe, in small amounts like a "no puddle", small filmy area is normal, even for gennys that do not see maximum loads. Intentionally overfilling the oil for a longer run time will make it worse. On high time 1,000+ hour engines it very slowly can get progressively worse.
When a 4 cycle engine runs, tiny/small amounts of piston ring blow-by gases will normally be generated into the crankcase air on every power stroke. The back side of the piston also generates rapidly pulsating crankcase pressure changes that make it harder to separate the oil mist/droplets from the outgoing gaseous air. Small one cylinder engines have simple, sometimes primitive vapor separator filters and floating plastic disk check valves that reliably allow only airflow outward with a filter mesh capturing the oil mist thrown off of all the moving parts inside and the blow-by vapors while gravity drains that liquid oil back into the crankcase all while the piston goes rapidly up-n-down in the bore. It can sometimes be slightly overwhelmed by sustained heavy throttle, especially at high RPM heavy loads in hot weather.
I ran my new 7.8 hour runtime inverter genny for 46.3 hours (house power) during hurricane Irma on eco-idle with occasional rev-roars to start a refrigerator, a chest freezer and the worst of all; an over stove microwave's magnetron cycling on/off/on during a 60 percent power food reheat setting. It sounded just like a power washer, with heavy loads separated by shorter rest periods. When the utility power came back on almost 2 days later I fully drained the fuel system and checked the air filter for any inhaled debris carried by the high winds, where I found something just like you did. A short length oil film emanating from the valve cover crankcase breather hose end. The thin film oil patch on the air box wall stopped at the bottom of the air filter gasket, without staining the paper filter element at all.
Moral of the story; Regularly check the airbox, especially after heavy load usage and wipe away the film without a worry.
Thanks. Yep, I read that post after searching the forum. After filling to the specified level the situation has corrected, however, I have noticed a very small amount of oil coming out of the oil level sensor plug (grommet). I have not pulled out the grommet to inspect, mainly I tried to push it to check if it's all the way in, but still there is a small film of oil that escapes. Maybe when I overfilled some pressure unseated the grommet?
I think I'm going to order a new oil level sensor, however I noticed they don't sell just the sensor up to the quick connector but the whole assembly.
Yes, the sensor cable goes through a hole in the block (just above the oil fill), and its behind the starter motor. There is a rubber grommet on the cable that seals the hole but allows the cable through. There was oil seeping through the grommet but now that I'm filling to the correct level it has stopped. Have not found any oil on the bottom tray in 3 days.