I bought a used (780 hrs.) 61" Wright Sentar zero-turn end of last summer from a landscaper. I think that it is the 2nd generation because it has the oil cooler above the engine. Didn't get to use it then, and mowed 2X this summer before changing oil and filter. The gasket above the flywheel starting leaking oil badly soon thereafter, then I had the mechanic previously employed by the landscaper for working on these mowers pick it up for servicing and adjusting steering. He informed me that a magnet was broken or dislodged from the flywheel and had to order a new flywheel, and that "everything else in the engine looked good". After he installed the new flywheel and reassembled motor, he called to say that the engine quit while he was running the mower and trying it out on a lawn; his prognosis is that the housing or crankcase into which the top sleeve or bearing of the motor is mounted is worn out and the motor will have to be replaced. I have not seen the engine since he called, since he lives in another county. The original motor is a Kawasaki 25 hp FH721V/Spec BS07 or AS07. Wright now uses the same engine, but with Spec CS33-R, with cylindrical Donelson air filter. I didn't anticipate this at all, and I have several options: (1) Buy a new exact replacement 25 hp Kawasaki engine for about $1650 - $1750 plus shipping and installation. (2) Buy a "new" surplus Kohler Model LV625 20 hp liquid-cooled engine for about $590, assuming it will fit, be compatible, and have sufficient power for non-commercial use. I can also inquire about similar Kohler liquid-cooled engines with more horsepower if needed. (3) Buy a "new" surplus Kohler 25 hp V730S-0028 (one available Spec #; although the Kohler that Wright used before switching to Kawasaki's 25 hp was Spec # -0007). The V730S-0028 will cost about $680 - $730, plus shipping. I think that these surplus engines may have only a 90-day warranty. I am not in the lawncare business, but bought the mower to have an ultimate personal mower for quickly mowing 1-2 acres now, and maybe more later. I don't know if I should consider selling the mower in a year or two and if this possibility should influence the choice of engine now. What do you advise I replace the engine with? Basically, I can get a surplus Kohler which may work on the mower for about half the price - or less - of a direct-replacement Kawasaki (from a dealer). If I could find the Kawasaki or a compatible Honda engine at such a good price, I might would buy that instead of a Kohler. I've read of some of the Kohler engines Model V730S failing because of the bolts used for the head gasket, but perhaps these Kohlers wouldn't have the problem. Would the liquid-cooled Kohler would be best of all if it fits and is electrically compatible? Do you advise yet another engine besides these? Thanks for advising me as soon as possible.