Some say it's just mopeds...others say you must get special super $40+ per gallon oil.
It must meet JASO, or ISO spec, and you must spend mucho dolla to aqquire it.
The thing is you can spend the big bucks, but you still will hear of flaws. I've heard synthetic has issues with corrosion, race oils can require frequent engine rebuilds. . etc. .
So then you're stuck in a situation where you are spending big money, and buy small bottles of oil that still is questioned by some.
I get the gallon of the cheapest walmart marine oil and I run it. No tiny bottles and big buck spending for me!
You will find people who say that you can't run marine oil because the mopeds are air cooled and the outboard engines are not. Let me tell you I've ran and left my engine idling for 10 minutes in 95F weather on marine oil and no seizure or trouble came of it.
Then again I pressure tested the engine when I rebuilt it and continue to check for air leaks! That's what seizes engines! Air leaks or not enough oil! Make sure your ped isn't sucking in air and give it enough oil in the mix and that's enough!
32:1 Cheap dino oil, The choice of non neurotic stock/slightly modded moppedders.
If you've got a powervalve or spark arrestor or high compression maybe not the best idea.... but if you're just mopedding along the oil of the sea will float your boat...er..hmm...moped!