I too have mulled what weight oil to use in my generator and other OPE. I've come to the conclusion that if it's a splash lubed system to use a 5w-30 just because I want the oil quickly flowing down the block to the sump so it can get splashed around again. I don't want a 40 or 50 weight taking more time getting back to the sump to get dispersed again. It's doing no good hanging out of the walls of the block while on it's way down. The main thing is the small amount of oil they often hold. 16 ounces isn't much if it's not getting back to the bottom of the block. To me, a constant flow of thin oil is better than no or a small amount of a thicker oil any day. And since the system isn't pressurized, seems to me that a thinner oil will get into tight areas better than a thicker oil will. Changed every day in extreme conditions should keep it fresh enough to protect the engine. And, I don't trust the low oil cutoff either because I think there would be enough residual oil on the switch to keep it from shutting the ignition off and not necessarily enough to lube the engine. I use Pennzoil Ultra Platinum 5w-30 in all my OPE. Pressure washer, snow blower, push mower, and generator.
As far as pressurized systems, I run Mobil 5w-40. I like the idea of the slightly thicker oil in an air cooled engine but the splash lubed systems just don't hold enough for my liking. And even being filtered and pressurized, I usually run 50-75 hours on a recommended 100 hour change. It's cheap and I change the filter every other time...the manual recommends 200 hours on the filter BTW. On a hot day, I have used my infrared heat gun to measure the oil temperature and have seen as high as 265 degrees for hours on end.
As far as pressurized systems, I run Mobil 5w-40. I like the idea of the slightly thicker oil in an air cooled engine but the splash lubed systems just don't hold enough for my liking. And even being filtered and pressurized, I usually run 50-75 hours on a recommended 100 hour change. It's cheap and I change the filter every other time...the manual recommends 200 hours on the filter BTW. On a hot day, I have used my infrared heat gun to measure the oil temperature and have seen as high as 265 degrees for hours on end.