Howdy all. So, I have now had my Sea Doo for 2 seasons. The first season, I basically rebuilt the thing from the ground up, minus the motor itself, and had a nice time riding it and getting to know the machine. Last season was my 2nd, and a spectacular one at that. My untouched OEM motor has 150 lbs. compression in each cylinder, and runs outstanding. But, in the event that it blows up one day, I wanted to have a spare motor around, ready to go. In my first year of ownership, I was able to source an all original motor with low hours from an identical machine like mine. This winter, myself and a good friend who knows these motors inside and out are going to rebuild it, and try to see how much power we can make, just by making it breathe better. I will do my best to document the tear down and rebuild. Stay tuned, but for now…
I’d put new Pistons and rings and hone the cyls quick with a ball hone (as long as they aren’t really trashed). The rotary valve area looks pretty good in the pics so I’d leave it alone. I wouldn’t go crazy raising the compression much, but a conversion to dual mikuni carbs would net a decent gain. Not sure if there is a better pipe/waterbox that might fit from another model… If it is oil injected I would personally keep it and bump up the injection rate by making the injection pump cable tighter… All the issues people typically have with the oil injection generally trace back to the oil injection lines and inline filters. If I were you, and you didn’t plan on splitting the lower case apart, at least look for rust/corrosion in the inside of the bottom end through the top with the cylinders off. If it looks marginal I’d def split it and look/feel the main bearings (ball bearings) it would just suck to get it in the ski and running just to hear a bad bearing grinding away in there…
