Brand new Pony w/mulching block installed. It does not mulch on first pass. It is necessary to go back over each row after it has been mowed. Instead of getting a discharge "line" at the side, there is a discharge "line" beneath.

Hi,
Well, mulching is a bit different than just mowing in that engine (and thereby blade speed) are critical in addition to slower ground speed and not cutting more than one-third of the grass at a time (a recognized requirement without regard to manufacturer.)
Peace,
Clarke