EXO Jet-Ski Everybody hates Jet-Skis. Even the people who ride them. It’s because they stink, they’re noisy and their cooling systems pump fresh water through the engine before spitting it back out as polluted water. The zero emissions, zero pollution EXO Concept is a new breed of clean-running Jet-Ski that may just signal a fresh, new chapter for the most hated watercraft of all time.