A while back I started a thread comparing the YM2000 air filters I have encountered.
http://www.tractorbynet.com/forums/yanmar/212635-yanmar-air-filter-elements.html#post2431294
I'll repeat the first post here. I suggest reviewing that thread for the useful responses that were posted.
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Some air filter elements for YM240/YM2000 and similar.
Back row from left:
Yanmar #124295-12560. 4.5" ID, 7.5" OD.
Yanmar-USA shipped this larger element (7.5 inch) when 'element for YM240' was requested.
Back row center: Yanmar #124450-12510 (the # in YM240 Parts Manual). 4.5" ID, 7" OD.
NOS filter I found on Ebay.
Back row right: NAPA #2297. 5.5" ID, 7" OD.
Front row:
AC #A127C, a replica of the Yanmar 124450-12510 behind it.
Found this on my YM240 in 2003.
All the filters except NAPA are 2 3/8 inches tall. The NAPA is more than 1/8 inch taller. The enclosure lid wouldn't seal so I took it back. (Also - this photo shows the NAPA filter has less surface area).
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Added - I don't think AC has made that filter for years but its number might be useful to find a cross reference.
But - just order a filter from Hoye. Decent price and good quality.