They should be changed every 2-3 years. Here is where you can see more of your motor. You will have to change it to match your motor as I just guessed the serial no. Mercury Outboard Parts Catalog - Mercruiser Mariner Parts
That is my lower unit. According to this drawing I had all the holes competely under water when starting the engine, all six holes on each side. I stuck electric fence wire in the holes to check for obstructions and found none. So my waterpump is probably bad? How often do these need changed? Was changed just last year. Would like to know were to view this drawing. Thanks.
They should be changed every 2-3 years. Here is where you can see more of your motor. You will have to change it to match your motor as I just guessed the serial no. Mercury Outboard Parts Catalog - Mercruiser Mariner Parts
Fair Winds and Following Seas
Bill H. PTC USN Ret
Chesapeake, Va
If your boat has been sitting outside it probably has dirt dobbers nesting in the top pee hole. Happened to me before...Take something flexible and run into the hole.(top hole where the water comes out) Hope that helps...
But one thing I do: Forgetting what is behind and straining toward what is ahead, I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus.