Thanks for your adviseIf you can't find it through JD or other lawnmower sources, try local industrial bearing supply houses or McMaster.com or MSCdirect.com
You'll need the O.D. of the shaft sealing surface, the O.D. of the seal and and the width of the seal.
Thanks for the help. The site you provided did the trick. Found my part number.John Deer have all their parts breakdowns on line at https://partscatalog.deere.com/jdrc/search IT will probably show mu local dealer but ignore that,
Dial in your mower and look for the engine section then the oil seal.
Conversely go to your engine makers web site and do the same thing.
With the part number they are available every where.