I have a 1995 Four Winns 5.0 with 170 hours. Other than dealer winterized inc oil change and outdrive service each Fall since new, never had any maint and has run flawless. The boat has been stored inside unheated garage since Sept 07, so the last 2 summers it was not put in the water.
Not mice nest, belts, hoses ... but mechanical/motor checks that should be done beyond a visual. Or something that could go bad - because of 2 plus years of storage ?