Do I have to use a mercruiser water pump?

[rabristol]

I have an inboard/outdrive 6 cylinder motor on my boat and the motor is a Is a GM 250 CID MCM GM 6 cyl. Do I have to use a boat waterpump or can I use an automobile one. Is it the same waterpump>

Thanks,

 

[woodrat]

Re: Do I have to use a mercruiser water pump?

I used a NAPA water pump on my 120 GM merc. It certainly fit and worked just fine. It appeared pretty much exactly the same as the one I took off. I don't know if it is different material somehow or whether it would last as long as a "marine" version, but $140 buys a lot of $25 water pumps....

And I HAD $25 when it went. I didn't have $140.

 

[wire2]

Re: Do I have to use a mercruiser water pump?

An auto pump will look the same on the outside but uses a steel impeller, which will rust quickly in raw water. It's meant to pump an anti-freeze mixture. A marine one will have a corrosion resistant impeller and probably better seals.

 

[woodrat]

Re: Do I have to use a mercruiser water pump?

I'll bet the one I took off then was also a automotive part, because it had a rusty, steel impeller in there.