Regal 3300 Owner's Manual page 119

Fuel Filters
environmentally safe fashion. In-line water separator filter is previously
shown. Refer to engine manufacturer's manual for additional
information.
https://www.boat-manuals.com/
Outboards use a 10 micron-style water
separator filter which is a spin-on type
similar to an automobile oil filter. Its
main purpose is to trap dirt particles
and condensation in fuel. If the fuel
becomes contaminated with water, the
water separator filters must be replaced.
It is a good idea to keep an extra fuel
filter on board along with a filter
wrench, catch container and clean rags
for emergencies. Never use automotive-
style fuel filters on your vessel. Dispose
of all fuel residue materials in an
Systems
4-7