I agree with Pau Hana and Skiperdude.
A little bit of a product may be good, but that does not mean a whole bunch more will make it better.
Sometimes the hype to sell products such as ZDDP - Zinc dialyldithiophosphate, which is an additive in many motor oils reaches the level of "snake oil." The EPA studies show that motor oils contain from 1-3% ZDDP which is sufficient to properly lubricate reciprocating engines and not pose an environmental threat. ZDDP at higher levels does pose health concerns and in the case of automobiles, the manufactures say, it can cause damage to the catalytic converter.
As suggested, use a good motor oil, such as Rotella or Delo, a good filter, and change the oil as recommended by the manufacture. You should be good to go.
P.S. Be sure and wear appropriate gloves when changing your oil, no skin contact as it is a biohazard.
Careful . . .I Have a Generator and I'm not afraid to use it !