Why does that happen ?

[Mikey N.C.]

The ski in pic is a sea foo with intelligent suspension. The helm and seat, are separate from hull and moves up and down for specific ride options. So motor compartment has a cover underneath seat and helm. That cover has a rubber gasket when it's bolted down to hull 18-20 bolts. If skis are docked for long periods , and water sets in foot funnel, water leaks passed seal into motor compartment. Running in rough water causes this or just riding ski hard with lots of water coming aboard will cause this, they have vacuum bilge not electric unless added. The problem with those skis is you can't just pop off seat and look. Ski may be half full of water once put in water. If drain plugs haven't been removed. If no exhaust water leak in motor compartment.
As far as carbon seal on a 4 tech . I assume they are talking about carbon ring on driveshaft and it that failed it's because they ran to long on hose out of water. You can't run for longer than 5 mins out of water or u damage seal.