Manual says to use 10w-30 API SJ oil. Honda oil is fairly cheap at around $8 a quart, and available at Home Depot, Amazon, etc: https://smile.amazon.com/gp/product/B01H2FWWSI.
Of course, I’ve also read that API codes are backwards compatible, in which case I can use any 10w-30 oil made for cars which is easier to get and half the price. And then I was wondering if I can use synthetic blend or full synthetic, just like you can for cars. These days, the price difference is small and full synthetic is cheaper than the Honda-branded “power equipment” oil linked above.
So, what should I buy?