I've not even bothered to try the deck wash system on my 2544.
I always mow in the late afternoon or early evening, so the grass is very dry. It really doesn't build up at all then.
On the occasion I've cut early in the day or too soon after a rain and really pasted up the underside of the deck with goo, I just drive the tractor up on my car ramps and reach under with a plastic spackle knife and scrape off the glop. Not the most fun job, but the deckwash wouldn't ever get that much goo off without making a green pate' mess all over the place.
I also blow off the entire tractor with compressed air after every mowing. Really keeps it clean.
Chris