I believe a straight 30 weight oil will suffice.
SAE 30
For a Briggs & Stratton Intek engine "PH8170"
48 oz oil capacity
I recommend you use SAE 10W30 100% synthetic in any air cooled small engine. Any major brand is fine.
Intek Pro, Vanguard, and I/C engines are for heavier duty Industrial/Commercial applications. The cylinder has a cast-iron sleeve insert. Standard Intek and Powerbuilt have an aluminum cylinder wall. These are for general and consumer use. Diamond refers to a Diamond Bore cylinder, a special preparation of the cylinder for better wear and oil consumption.
Most single cylinder Briggs engines hold 40 oz of oil. SAE-30 type oil
A Briggs and Stratton 17.5 horsepower engine can use any type of small engine motor oil. A heavy duty motor oil is recommended.
SAE 30
SAE 10W30 synthetic oil.
what grade of oil on this engine
Assuming it is a Briggs & Stratton GenTec Pro Intek V-Twin & ELS it will take 60 ounces + 4 more ounces if you also change the filter.
Basically all Briggs engines call for a high quality 30Wt