I have no doubt that any motor oil certified by API and in the recommended weight be should all that is needed to make your motor run as long as don’t tire of it. The amount of oil is minuscule compared to a car, often with out a filter. Why mess around for a minuscule savings ? But, I have no doubt that the frequency of oil change is just as important and if you used this gift oil and changed it twice instead of once a year, it would be fine. But I STILL would Use what is recommend in the cheapest oil you can find and it might cost less then $5 per year.
Take the gift oil and donate it to someone who has a waste oil furnace.of course, I would use it as a rust preventative measure but you can do what you want. Once in a while, I treat my lawn mower to Kubota tractor diesel motor oil or synthetic oil I use in the winter when I have enough of it lying around. IMHO, it’s desert for the lawn mower where I normally just use regular oil.