Another mower was adopted today by me

[CleanSump]

Appreciate this. But, will continue to run whatever automotive synthetic multigrade is kicking around in my five Honda small engines, all more than 20 years old, none with any discernible oil consumption. But thanks again, I did not know the straight weight oil offered this advantage.

I've always used what was left over from 5 qt jugs from my cars' oil changes too! I just wanted to share what I've read here over the years to answer your question.

 

[4wd]

Change the oil to conventional SAE30. Nothing else. A synthetic is much more likely to smoke on a old seasoned engine like that. Smoking might go away or diminish with the SAE30.

(I've owned literally thousands of mowers, bought and sold, over the years as a side hustle. Synthetic WILL smoke in old worn out engines while conventional SAE30 wont. Just something I learned over the years)

That’s interesting - B&S continues to sell the mono. Recently put SuperTech HD30 in my Kohler 5400 for the summer.
Sounds great!