What's different about marine circulation water pumps (Mercruiser 3.0)

[cheburashka]

I got my boat out of storage today (Mercruiser 140 3.0) and when I turned the engine over by hand, there was a nasty grinding sound. It turned out to be the water pump bearings. I pulled it and it was riddled with rust.

I know there's no antifreeze in these cooling systems so the pumps will rust out eventually, and this one was probably original to the boat, which is a '72, but I'm wondering if some companies make marine water pumps that aren't as easily damage by rust. I don't want to be replacing this thing in another 35 years. . .

Seriously--are marine water pumps made with rust-resistant materials? Is the Sierra (the most commonly available pump) a good choice, or is there another I should look for?

Thanks

 

[firehog6305]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

I am sure that there is water pumps for that motor from sierra, but 35yrs??? you are going to be lucky to get 10yrs out of a marine application anyways.
the best way I found to find if its a marine part or not, is take the part number down to the auto parts store, if they have it, its auto, if not its marine. I know thats someone will jump in and give you more info and suggestions soon

 

[BAYLINER185]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Sierra parts are fine and they are made for your boat. They are marine parts.

I think the only differance between an auto watewr pump and the marine pump is the impeller is brass in the marine pump Vs steel.

Just put the seirra part on and go enjoy your boat!

 

[Don S]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

On a marine pump, the bearings and front seal are heavier duty. The backing plate and shaft are SS.
With a raw water cooled engine, stick with a marine pump.

I would never put a Sierra part of any kind on my personal boat. Unless it was impossible to find anywhere else.

 

[TollyWally]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Don,
Are there aftermarket replacement parts that you feel offer a good value for the money? My Volvo is well engineered, but the factory parts are priced close to the outside edge of the envelope. What is your opinion of Barr, Osco, etc.?

 

[Coors]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Don,
Are there aftermarket replacement parts that you feel offer a good value for the money? My Volvo is well engineered, but the factory parts are priced close to the outside edge of the envelope. What is your opinion of Barr, Osco, etc.?

Because the state refuses to issue a license.

 

[TollyWally]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Because the state refuses to issue a license.

I'm not quite understanding your post.

 

[cheburashka]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

I was just kidding around about the 35 years. I've only owned this boat for two years and the pump was doing its job without complaining, so I saw no reason to replace it until this season.

So where would I go about finding the OEM part? I've searched for the OEM stock number 65142A1 and all I get are references to Sierra's 18-3575. Iboats doesn't carry it. Nobody I could find has anything in stock except the Sierra.

I'm also a little confused by the specs of the Sierra. West Marine says:

Available features:

* Brass impeller
* Brass plugs and fittings
* Carbon resin seal
* All mounting gaskets
* Stainless steel seal cup and spring
* Stainless band ceramic seal cap
* Stainless steel back plate (where required)
* Powder coating for maximum corrosion protection.
* Pumps are bi-directional.

These are "available" (and most of them weren't there on the original pump) but does that mean that all Sierra pumps have these features?

 

[rndn]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Why do you want to replace your circulation pump if it was working fine?

 

[cheburashka]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

Why do you want to replace your circulation pump if it was working fine?

Rust in the bearings and on the impeller. It made a scraping sound when I turned the engine over. I figure the fewer "normal" noises I have in an engine, the easier it is to diagnose the ones that aren't normal.

Also, there's a lot of rust on the pump body, and it's at three times its expected lifespan.

 

[Coors]

Re: What's different about marine circulation water pumps (Mercruiser 3.0)

I'm not quite understanding your post.

lost copy/paste that ended here; sorry