Water pump(s)?

lombard · Jun 30, 2008

So, I think I may have gotten a bit ahead of myself. Pulled my boat out of the water without realizing my buddy failed to turn off the engine. Seemed to run fine on the muffs when I was flushing it at home. But, just to be safe, I decided to check my water pumps before getting stranded over the 4th of july.

So here's my problem...

'95 Mercruiser 4.3 Alpha One, seawater cooled.

For some stupid reason I decided to start with the pump mounted to the engine. Following the maintenance manual, I removed the pump without a problem. I've got a fair amount of rust around the small holes on the front of the housing (near the pulley shaft). There seems to be a small amount of binding when I spin the pump by hand. There's no wobble in the shaft, but I haven't been able to inspect the impeller. I took the back plate off the pump housing. Any advice going forward? Are there rebuild kits for the average DIYer with these pumps? Or at least new gasket kits to reassemble the pump? The manual just says to replace the pump if there are any problems.

Haven't gotten in to the water pump in the outdrive yet. Is this the pump that tends to have impeller failures when running dry for a short time?

Don S · Jun 30, 2008

Re: Water pump(s)?

You have 2 pumps.
A sea water (aka raw water) pump located in the outdrive. It's the one that has the rubber impeller that needs to be replaced as preventive maintenance.
Then you have the engine Circulation pump. This is what automotive types call a water pump. On a boat, it's a circulation pump. Why you ask? because all it does is circulate the water that is in the system, it doesn't pump anything really. 99% of the time, when a circulation pump is the cause, it's because it's leaking or noisy and leaking.

Here is a link to the Mercruiser service manual for your outdrive. you may find it useful.
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/14/14cover.pdf

lombard · Jun 30, 2008

Re: Water pump(s)?

Thanks for the vocab lesson Don. I already have the service manual. Just haven't gotten in to the seawater pump yet.

As for my circulation pump....any rebuild kits or advice on further disassembly to inspect the impeller on it? At the very least, I'm going to need a new gasket to reinstall the back plate on the housing. Then of course, I'll need the new gaskets for reinstalling the pump.

I'll get in to the seawater pump tomorrow probably.

chiefalen · Jul 1, 2008

Re: Water pump(s)?

That circulation pump is over 13 years old. You using it in saltwater? Cheap

to replace. If it were my boat, I would put a new one on.Comes with everything

you need. Just make sure you get all the old gasket off. Perfectly clean surface.

lombard · Jul 1, 2008

Re: Water pump(s)?

Thanks chiefalen. We're thinking along the same lines here. I just need to call around to see what a new one is going to run. I figured rebuilding would be pretty easy (and possibly cheaper). Possibly not though, because it looks like I may need a press or something to disassemble the impeller/shaft and bearings.

lombard · Jul 1, 2008

Re: Water pump(s)?

I've called a couple of local places. New circ pump is going to be ~$120, for Mercuiser OEM. I've got no problems paying that much, but if there are better deals around, it'd be stupid not to look. So what do you guys think? Am I looking at a fair price?

Gary H NC · Jul 1, 2008

Re: Water pump(s)?

Price one here at Iboats or check Ebasicpower.com...Napa auto parts can get the Sierra line of parts too.

lombard · Jul 1, 2008

Re: Water pump(s)?

Thanks Gary. Good idea. Are the Sierra's OK? I'd hate to spring for one to save $40, just to have it fail sooner than an OEM.

HT32BSX115 · Jul 1, 2008

Re: Water pump(s)?

From Ebasicpower

[FONT=Arial, Helvetica, Sans-serif] Part Number: MPR2232MN
Price: $69.95
Weight: 11.00 lbs

I think that one is the right one for your engine (you need to check to make sure)

You have to pay shipping and wait for it to be shipped. If you're not in a hurry then it's probably a good deal.

There's lots of deals out there on the net including right here on iBoats...

Cheers,

Rick

[/FONT]

chiefalen · Jul 1, 2008

Re: Water pump(s)?

Ht3 seems to have found one for you. sounds about right price wise. I bought

from e-basic power myself. Maybe just check ebay before you order, never

know whats there.

lombard · Jul 1, 2008

Re: Water pump(s)?

As is usually the case, I'm trying to get the boat ready for the 4th of July. So, I'll end up paying a higher price for more immediate use.

Called NAPA. They sell the Sierra model for $135.00. Guess I'll just hit the dealer close to home and pay for the OEM pump. Lesson learned...

hard-3 · Jul 1, 2008

Re: Water pump(s)?

just an fyi I found a replacement circulator pump for my 7.4 merc at oreillys auto parts. They were able to look up the casting # from the old pump and match it up with a replacement for a 1968 camaro with a 402 . There is a number cast into the pump . the first counter girl was not up on this but a guy was able to get out a book and look it up for me. Most of the so called special mercury parts are from GM. The difference is the rotation and the length of the shaft sticking out . I'm all for supporting the guys that keep this site running, but the 4th is 3 days away
Jeff

Maclin · Jul 1, 2008

Re: Water pump(s)?

The housing casting number may match but I am thinking that the innards won't. You probably will not end up with the correct Marine pump that way. I'm just sayin' that "....the difference is the rotation and the length of the shaft sticking out ..." are pretty big show-stopper type diffs.

lombard · Jul 1, 2008

Re: Water pump(s)?

Yup, the 4th is 3 days away. Which is why I'll be paying $120 from my local dealer. Still cheaper than the Sierra from NAPA.

hard-3 · Jul 1, 2008

Re: Water pump(s)?

I thought that too , so i took it apart and compared before I installed. On the 7.4 in my boat it was identical to the original that came off. same impellar, same shape. the only difference was a plug was needed to plug off the heater hose port that was not used.on some later models the rotation might be different.I just took off the cover and compared them , resealed cover and put it on. worked fine for 2 seasons. and has lifetime warrenty !
Jeff

Fishermark · Jul 1, 2008

Re: Water pump(s)?

I would be surprised if they were exactly the same. Does yours have a brass impeller and a stainless steel cover? If so, then yep, they're the same. If not, then yours may work fine for freshwater, but will disintegrate in salt water.

chiefalen · Jul 1, 2008

Re: Water pump(s)?

Boats that never taste saltwater are a pleasure to work on. My 1976 Evinrude
never tasted saltwater. Look under the cowl and you would swear your looking at a new motor.

Bondo · Jul 1, 2008

Re: Water pump(s)?

I would be surprised if they were exactly the same.

Ayuh,..... Same Here.....

My 1976 Evinrude
never tasted saltwater. Look under the cowl and you would swear your looking at a new motor.

Ayuh,....

My 1954 5,1/2hp Johnson is the same way........

lombard · Jul 1, 2008

Re: Water pump(s)?

Dug in to the lower unit tonight. Water pump was in great shape. Impeller looked (and felt) brand new. Going to clean up the plate and housing and get some new gaskets and reinstall it.

While I was in there, I decided to check the oil seal (right below the pump). Holy crap! I swear that thing hasn't been checked since the engine was new. It wouldn't budge. I ended up going after it with a hammer and chisel. Had to destroy the carrier and O-ring to get it disassembled. Going to buy a new one for installation tomorrow. Need to clean up the installation area enough to get everything reinstalled and well sealed. Argh.

chiefalen · Jul 2, 2008

Re: Water pump(s)?

Good luck.

Water pump(s)?

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