Synthetic N should be fine.
It would be tough to find an F or H these days on the shelf of most places. The availability seems to be L, M, N these days.
Most additives above H I think are performance enhancers for big engines like cars and won’t do much good in a small engine.
I’ve read quite a bit about oils and the reward is I’m confused on specifics. Generally synthetic seems to be a better lub than fossil based. There’s probably not a lot of difference between a quality fossil oil and a decent synthetic but again the better products seem to have enhances that are not relevant to a small engine.
One puzzle for me is the shelves of products have ratings that companies must meet to display the rating label. You can find 10 oils on the shelves which differ substantially in price and all are N so what’s the difference? Most companies don’t surpass required spec’s.
They also make claims that are broad and vague which they are not so responsible for. How do you know you’re getting anything for the money buying a cheap versus expensive oil especially for a small engine? Most of the claimed enhancements apply to big engines. An LDO claim may be true but what good will it do in an 8hp Tecumseh or Briggs running 20-30 hours a season?
Most of the very old engines I see that ran on supposedly low quality oils than available today are still running. Many are compression degraded and maybe they would have been much better off if they could have been running N grade or newer synthetics. Tough to say. There is also the vast majority of old engines that are not alive and kicking.
Depending on the mood rather than knowledge I’ve run medium to quality fossil in the Hondas and Yamahas and a few time high end synthetics. These days I mostly use low end synthetic oil from Walmart. It’s got the same ratings as the better synthetics and I can’t deal with the claims past ratings they must comply with. I can’t tell from my equipment if low price or high price oil makes a difference. I also can’t tell if using fossil or synthetic makes a difference. From my reading there is a general lub advantage to synthetic oil so I use mostly synthetic. Changing oil is very important. What you change with is not so important.
