My guess is that it will come with an Owner's Hand Book and it will recommend how to break it in which is what I would do.

Walt Conner

What he said. Most likely it will say to use it normally with the recommended oil, then change oil and filter after a certain number of hours.

Warm the engine up then cut at full throttle. A load on the engine will do a better job of seating the piston rings. Bearings don't need any break-in time. Oil & filter at 5 to 10 hours is not a bad idea.

Should I switch to FULL SYNTHETIC motor oil after initial break-in ?? Is it beneficial in small gas engines ???? Especially in hot & humid Florida ????

Wouldn't hurt but I think regular oil changes are more important on a dollar spent basis.

The break-in procedure for our Ariens snowblower was simple to follow. "Operate as normal, and change oil after 3 hours of use." There is no oil filter to change out on this machine.

As others noted, there should be as much break-in for your lawn mower as is indicated by the manufacturer in the owners manual. Take some time to read it through BEFORE starting the lawn mower.