My front swivel Ariens finally died. It had a 5.5 Tecumseh engine

The new Ariens LM21SW Has a Kohler or Kawasaki 6.0 motor.

Not sure what the better motor is, they are both $650

Any other suggestions for a mower?
I have never used a mower with straight wheels, the swivel wheels let
the mower go around my landscape.

I looked at the John Deere, but it has a Briggs and Straton Motor -
not sure how good those are.