Yamaha - Z300 Water Intrusion Kit Engine Protection Kit 90891-40689-00. Overview. Water intrusion is one of those problems you don't want to discover the hard way. I've seen Z300 setups where everything looked fine on the outside, but moisture got in and caused bigger issues down the line. The Yamaha Z300 Water Intrusion Kit 90891-40689-00 is built to help prevent that before it starts. It's a smart add-on if you're running hard or spending a lot of time in rough or wet conditions.. Key Features. • Water Intrusion Prevention - Helps block moisture from entering critical engine areas.. • Z300-Specific Design - Engineered to match Yamaha Z300 configurations and fit points.. • Protects Internal Components - Reduces risk of corrosion and internal damage.. • Durable Marine Materials - Built to handle constant exposure to water and harsh environments.. • Complete Kit Solution - Includes necessary parts to properly address intrusion concerns.. Engine & Boat Compatibility. The Yamaha Z300 Wate