Alpha 1 gen 2 lower unit water pump life expectancy

[Lowlysubaruguy]

I replaced the lower unit water pump yesterday its the original boats a 1996 Mercruiser alpha 1 gen 2 4.3 with many hours of run time in 97 Its only been in salt water twice but its been stuffed on a few sand bars and has quite a few hours on it.

My original water pump looked and felt like the new one. I even tried to force the blades to show any cracking or signs of degradation. Its only seen salt water 2 times so I cant say what salt water would have done to it but I was expecting to find the impeller blades worn out or ready to disintegrate?

Ive read about people replacing them every 5 years or so and that any sand will eat them alive?

 

[GA_Boater]

Buy a lottery ticket. You were on borrowed time with 22 years on the original impeller, no matter how it looked and felt.

Salt water or fresh water use has not one thing to do with the life of the impeller. 2 or 3 years is the recommended replacement time.

 

[achris]

The long vane impellers used on the gen II's is very impressive. I've seen them over 10 years old and still looking and feeling like new.. as mentioned, recommended service interval is 3 years, but in a stretch 6 shouldn't be a problem... Where the problem is, is when the other things that should be check far more regularly get neglected...

Chris....

 

[Scott06]

Last summer I helped my neighbor change his gen II IMPELLER - ten years never changed as he bought boat new. My boat was 11 years old when I got it impeller also looked new. Both of these are relatively lower hour use but seems like ten years is not unheard of, but I doubt I’ll push it that long. Probably the 3-5 years mentioned above is a safe bet.

Makes it worth getting the OEM Merc kit for $50 vs aftermarket

 

[achris]

Makes it worth getting the OEM Merc kit for $50 vs aftermarket

Exactly. Not sure I'd trust an aftermarket more than a couple of years... 5 times the life makes the Merc $50 kit incredibly cheap.

Chris...