Originally Posted by pstorti

you should check and see what the recommended service interval is for the pump, I used to change mine every year when I had 496's, but with the Yanmars they recommend every 4 years or 1000 hours!! I changed them at 350 hours which was about 3 years, they weren't perfect but still intact and pumping well. I would hope Merc improved the pumps on the new engines. Unless you are constantly sucking up sand or it is recommended every year you can probably wait.