New to the group, but got a service manual with my new boat and use several K&N filters on other applications.
The air filter can be cleaned with soapy water, rinsed, air dry for at least 30 minutes until dry (water from garden hose "without" spray nozzle, use soap/cleaner, do not use brush, be gentle).
I plan to use K&N cleaner when I clean/oil the filter. K&N has a filter kit that includes cleaner & oil. K&N or p/n 219 700 340 oil (service manual #) can be used on the filter after cleaning & drying. When I oil K&N filters on motorcycles & cars, apply "lightly".