My old 1992 Generac 8HP Brigs says 30wt so had some for other lawn stuff and compressor. But the new BlackMax with Honda GX390 says to use 10-30 Synthetic. So bought 2 cases of 12 on sale from Sam's Club delivered.
Then only located one bottle of the old 30wt Napa Dino in my cabinet used it for the next Gen oil change. I had more of the 30wt Dino but did not take the time to find it. So used the 10-30 Mobile One synthetic. the 10-3 made it use oil. not sure if it was due to synthetic or weight being thinner at 10-30wt instead of 30wt