How do I take the bottom spin arm off so that I can clean it out as I suspect that this is the problem?
Unscrew the spray arm cap (#34 on the break down diagram).
Remove the cover (#4) and clean the pump housing filter (#6) and the rinse arm (#7).
Here are the break down diagrams for the Maytag dishwasher http://www.appliancepartspros.com/partsearch/model.aspx?diagram_id=672517&&model_id=47622
Gene.