I just bought a 1989 Stratos 201 with a Yamaha 2.6l V6. The water pump is pumping, but when I run it for a few minutes the alarm goes off. The boat has sit for 1 1/2 years, so I belive I should change the pump. Is this something a weekend mechanic can do? if so is there some place that I can get step by step instructions? Thanks for any help.