I'm thinking that the "s" stands for short. Evidently most all applications went to the longer filter. It went from under 3" to over about an extra inch translating into more filter capacity. According to the guys at the site below it went through several improvements and is currently (June-2012) now this number
KOHLER 5205002-S1 OIL FILTER, EXTRA CAPACITY
ok, now here is a good bit on an Amazon review of
KOHLER 52 050 02-S1 by "Clint"
Kohler in their infinite wisdom has changed contractors in the construction of their oil filter. The black filter shown in the photograph may not be what is sold this year. They are selling a yellow painted filter using a Champion Laboratories "Eco" design. A quality oil filter has a metal interior with holes to allow the oil to flow through it. This metal cyclinder supports the paper filter element. The "eco" design uses a plastic grid with large openings. This does not fully support the filter and allows pieces of the filer element to pass into the engine. This naturally causes blockages which leads to engine failure. If you want a quality oil filter for your Kohler engine, use a Purolator L10241 (or PL10241) or the Wix 51348 as substitutes for this filter. The Champion Laboratores "Eco" design is probably worse than a Fram oil filter. I would give the currently sold "eco" filter a zero stars if that was possible.
KOHLER 1205001
What is your Goal - Not pay Sears prices for an oil filter? I bought a NAPA brand oil (1348) filter for my riding lawn mower with a 16 HP Kohler for $6.
No
What is the fram oil filter cross reference for kohler part# kh-52-050-02-s
12-050-01: Available at most Lowe's
That would be a Fram PH8172
PH3614
PH4967. Fram specifically says the Kohler 7.3E uses this filter
The Amsoil / Wix # is 51056
Yes.
Wix has a filter look up site that lists many equivalents. wixfilters.com The Wix filter for the Kohler 12-050-01 is a 51056.
Acording to the Fram Oil Filter reference guide, Kohler 12 050 01 s can be replaced with Fram PH8172.