If your lawn mower and other small gas motors (chain saw, etc.) are 5 or more years old they likely weren’t designed to handle ethanol in current gas. Most cars, 15 years old and younger, can handle the alcohol but older cars perhaps not. Boats and other marine engines are at a definite disadvantage and Marine additives to treat gas going into boats is very common.
The carb (4bbl Holley) on my ski boat ('87 w 351 ci PCM Ford block marine V8) had all kinds of a whitish, sand like, deposits likely from ethanol interacting with metals and plastics in the fuel system. Cleaned out the gunk and installed an new filter (hope it helps) and it made a huge difference in how the motor idles and runs.
These additives apparently do work, and should be used in “older motors” including lawn and garden equipment.