What regular maintenance should I do on my Honda jet ski personal watercraft?

[danman2_2999]

I have two 2005 Honda aquatrax (standard model, not the turbo) jet skis that I bought new that have about 50 hours on them. These hours have accumulated over about 4 seasons. I have done some basic maintenance each summer before storing them for winter, such as lubing up a couple joints and what not. However, the book suggests doing full maintenance for hours/months, whichever is first, and for sure time goes ** before hours do. I have only 50 hours, but for 4 years, what maintenance do I absolutely need to do? It costs about $150 each to have them done at a Honda dealer...and I know its probably real basic work so I would like to do it myself....please let me know what maintenance is required on my 2005 Honda aquatrax jet ski pwc. Thanks!