Without knowing your skill set it is hard to say, but I would rate pulling the pump off as a 2 on a scale of 1-10, if it is like mine you will have 2 small nuts to remove that lets you disconnect the steering and reverse cables, 4 bolts that hold on the steering mechanism and reverse gate (on each side if you have a twin engine), then 4 more nuts with washers and lock washers that hold the pump on. If it is sealed with silicone it is then just a matter of tugging and wiggling to get it free.
Alternatively you may be able to get enough of a view of the impeller and wear ring looking up the water intake, but this will not tell you much about an air leak around the pump.
If the wear ring is bad, it is a little more work, lets call this one a 4 on a scale of 1-10, you will need a bench vise and an impeller tool ($8 online) to remove the impeller, then the old wear ring will need to be cut out. These new style vibratiting multipurpose tools work great for this, like a hot knife through butter, and they only cost $20 or so at Harbor Freight. Once the old wear ring is out, it is a simple matter to install a new one, just freeze it and it may drop right in, if not it may need a little encouragement with a piece of wood and a hammer.
