late to the party but the manual on the 22" recycler I am working on is conflicted. It says 20 oz but it is full about 14 oz when fully drained. One part of owner's manual just says check with dipstick in then the next paragraph it says once oil level is ok then secure. A few paragraphs later it says screw dipstick in to check oil. I went with screwing the dipstick in. Most of my engines take slightly less than the manual states.
This is a quote from a 2015 thread on Bob the Oil Guy:
Briggs and Stratton:
https://www.briggsandstratton.com/eu/en_gb/support/faqs/browse/lawn-mower-oil-change.html
Quote: If the engine includes a dipstick cap, remove the dipstick and wipe it with a clean cloth. To ensure an accurate reading, reinsert the dipstick completely. Then, remove it again and check the oil level. If the dipstick cap is a screw-in type, ensure an accurate reading by screwing in all the way before removing it a second time to check the level. The oil mark on the dipstick should be between the lines shown on the dipstick (image C) . It should never be above the FULL line or below the ADD line.
Tecumseh.
https://www.manualslib.com/manual/510830/Tecumseh-Snow-King-Lh195sp.html?page=7#manual
Quote: Oil Fill Cap/Dipstick If your engine has an oil fill cap/dipstick go to step 1. If your engine does NOT have an oil fill cap/dipstick, see "II. Oil Fill Cap/Plug" instructions below. 1. Be sure engine is upright and level. 2. Unscrew oil fill cap/dipstick from oil filler tube and wipe dipstick clean. See Figures 8 and 9. 3. Screw oil fill cap/dipstick back into oil filler tube. Tighten securely. 4. Unscrew and remove oil fill cap/dipstick from oil filler tube. Note oil level. If oil reading on dipstick is below “ADD” mark, slowly add oil to reach “FULL” level. See Figure 7 on page 4. Afterward, continue reading instructions below. 5. Screw oil fill cap/dipstick back into oil filler tube. Tighten securely. 6. Wipe away any spilled oil.