Engine circulating water pump ?

[starsnstripers]

1970 merc MC-1 250cid 165hp Where im going to run a closed cooling system is it necessary to run a marine water pump? I'm not sure if the one on my engine is or not, can one identify it? Do the marine ones have a brass/bronze impeller and automotive have a metal one? Thanks, BTW= Happy Easter people!!!

 

[rndn]

Re: Engine circulating water pump ?

I would think if you're running a closed system with anti-freeze it would not matter if the pump was a marine version. I believe the difference is the impeller is made of brass and designed for raw/salt water.

 

[starsnstripers]

Re: Engine circulating water pump ?

Probably the bushings shaft spacers etc. brass too. But yeah if im running a closed system I cant see as it would matter, thanks.

 

[180shabah]

Re: Engine circulating water pump ?

One other difference is the SS backplate. Again though, if you are running in fresh water only, you don't have to worry about them rotting out as fast. In salt water they tend to last about 2 years before they rust from the outside in.

 

[JustJason]

Re: Engine circulating water pump ?

i don't know this as fact... but i heard through the grapevine that marine waterpumps (circulating pumps) have bigger/better bearings designed to run at high rpm... can anyone else out there confirm or deny that?