How often should an Alpha water pump be changed

[David]

My brother’s outlaws have a 4 Winns bow rider with an Alpha drive. It just overheated and blew a head gasket.

I suspect the water pump. How often should these be changed?

[TooStroked]

Generally speaking, about every 3 years. That said, any number of things can shorten the life of the impeller. For instance, if you wrap weeds or a plastic bag around the gear case water intakes, you can take a brand-new impeller out instantly.

The other thing that would concern me about what happened to your relatives is that the over-temperature alarm should have gone off well before the engine over-heated and took out the head gasket.

[FUJIMO]

...every year...

[Jim Speros]

Lets get more specific. First Alpha first generation. Manual states inspect every year replace every other. Salt or shallow sandy water demands every year.
A Gen II has a floppy vane impeller. Much more tolerant and can outlive the gaskets in the pump. 3 Years is a good interval in fresh water. Again salt and shallow sandy water shorten the interval.
Keep in mind the lube needs more attention and grease on splines should be done annually.

A meticulous person would service any annually regardless of hours.