I have a problem with one of my skis, It has been sitting for 4 years and just tried it in the water today. Ran good for the first minute or so, then it kept hesitating like you cut off fuel for a quick second, never seemed to get back up to top speed again after that. any ideas on what the problem could be? I am guessing fuel, if anyone agrees, what is the best way to clean out the system. I think the rave valves are ok, cause I was able to get the rpms into the 6k range.