Originally Posted by MarkofSeaLife
What??? Have you got shares in NAPA?
Change them once every 150 or 300 hours or whatever the book says, and have a spare or two but a case?
Obviously, you have never taken a motor boat to sea that's been in the third world for some time. I talk from experience, not as a stockholder in a filter company. Try having to change primaries every couple of hours on both engines, not 150 hours. In this case it's definitely better safe than sorry!