Honda GX50 engine (kid kart) - which motor oil to use?

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:

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? :wink:

I just run my Briggs oil in it. Well redline 20 wt. no issues yet.

Don’t over complicate things. It’s a low horsepower 4 stroke.

Presuming you mean Redline 41205 5w20, yes, I already have that so it’d be quite convenient… though it’s at least 2x more expensive ;-).

No I use 10205. Straight 20wt redline race oil