Need to figure out which water pump I need on OMC/Volvo

[CChase86]

I have a 1995 OMC Cobra 4.3GL, carb'd motor. I know this is some kind of strange cross-over year as the stern-drive itself is a Volvo Penta unit.

I need to order the circulating water pump (the one that sits off by itself on the accessory belt, I think that's the correct name for it) but I have no idea how I can go about figuring which one is the right one. Every way I search comes up with many different part numbers of wildly varying prices.

How can I go about this in an orderly fashion?

 

[zbnutcase]

Re: Need to figure out which water pump I need on OMC/Volvo

Post the serial number of the engine to start with please. 'nutcase

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

Thanks for the quick reply. Unfortunately (and this may be part of why I was having a hard time) I don't have access to the serial number because the boat is shrink-wrapped right now.

Am I correct to now assume that there's no way to find out? And what is the correct term for this water pump? It is not the one that would be on a normal car that's right in the front of the block, it's off at far starboard side on it's own belt.

 

[Don S]

Re: Need to figure out which water pump I need on OMC/Volvo

94 was the first year of the OMC/Volvo joint venture. I would look at this service bulletin, if you have an HU or NC model code you your engine full model number, then this service bulletin is for you. But, if you have an MD (94 model) engine, then you have have an odd ball pump not on the bulletin.

http://www.4shared.com/document/deCtomdc/Volvo_impeller_kits.html

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

How uncommon would it be for a mid-95 boat to have a 94 engine?

I am beginning to realize there may be no way to verify I can get the right part without the serial number from the engine, but I'd like to be able to do as much homework as I can now.

When I have ordered parts for the boat in the past I didn't get an indication that it was a one-off engine, parts were usually in stock... if that's any indicator, I guess. My assumption is that it's not a 1994 engine.

The piece I need is the housing itself. For whatever reason mine apparently has a crack in it... whether that is due to incorrect winterization (I don't winterize it myself other than changing fluids) I don't know (but also irrelevant).

So far the only place I have seen this pump is through Volvo Pentas online store, and only as the entire assembly, not just the housing. I was curious because there's about 15 different engine codes, but of the few I clicked on, the water pump part number appeared to be the same among all of them.

 

[Don S]

Re: Need to figure out which water pump I need on OMC/Volvo

How uncommon would it be for a mid-95 boat to have a 94 engine?

About a 50/50 chance. Engine year model and boat year models do not start at the same time.
I really doubt a Serial number will help if you have an OMC engine. No one here that I know of can convert the TXXXXXXXXXXXX serial numbers to anything. There is a model number that has 4.3 in it and a bunch of letters. That would do the same thing. Volvo and OMC also shared the spec number that started with a 3 and usually had 7 numbers.

While you may have gotten engine parts with no problem, that is because they were the same for several years. The impeller and the pump on the other hand changed several times.

 

[Gary H NC]

Re: Need to figure out which water pump I need on OMC/Volvo

I just replaced one on a OMC SX,95 model with the 6 inch pulley,
The Volvo OEM number is stamped on the pulley.

Take a look at these and match one up.
http://bpi.ebasicpower.com/c/VOL7E/Raw+Water+Pumps+for+Volvo

 

[Gary H NC]

Re: Need to figure out which water pump I need on OMC/Volvo

I just replaced one on a 95 OMC SX,They show several different pumps.
Volvo does still stock the original type.
Does it have 3 screws on the back of the pump housing?

Look at these,Original pump
https://www.marinepartseurope.com/en/volvo-penta-explodedview-
7748040-26-35407.aspx

Updated to this Sherwood pump,

http://bpi.ebasicpower.com/mm5/merc...er&Product_Code=SHEG-9901&Category_Code=VOL7E

 

[Gary H NC]

Re: Need to figure out which water pump I need on OMC/Volvo

Sorry on the double post...oops!

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

Thanks for all the information (everyone). I'm going to have to unwrap the boat, but not until the threat for snow is gone... I'll bump this back up if I have any questions then.

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

Part number of the water pump is 3851623 which is superceded by 3858847.

I am looking at the pump now. The marina told me they saw a crack in the housing which was letting water weep out. I am staring at this thing with a magnifying glass and can't see anything resembling a crack, even the paint is intact.

Is it possible the shaft seal is just dead and they are just saying it's cracked? I wouldn't have them replace it anyway as I have no problem doing it myself, but I'd rather get out of spending close to $400 for a part that I am not seeing a problem with myself.

I am wondering if I can remove the impeller and pressure test it with a garden hose and see where water might be coming out.

Any ideas/suggestions? Not looking out of fixing this the right way but I'll be darned if I can see this crack, and my eyes are plenty sharp for that kind of thing. Also, when I pressed them as to where the crack is, the mechanic vaguely pointed with a pencil up near the webbing where you can see the shaft exiting the case, which is another reason I am suspecting it is not actually cracked, as it's not apparent to me that water would even be in that area.

 

[dannyual767]

Re: Need to figure out which water pump I need on OMC/Volvo

That's the sea water pump you're talking about.

Why did the marina say there was leaking water? Did you have leaking water that you were aware of?

If you didn't have any problems that you were aware of, I'd just take the boat out and run it and keep an eye out for leaking water or temperature abnormalities.

You might want to consider an impeller replacement just for good maintenance and peace of mind.

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

That's the sea water pump you're talking about.

Why did the marina say there was leaking water? Did you have leaking water that you were aware of?

If you didn't have any problems that you were aware of, I'd just take the boat out and run it and keep an eye out for leaking water or temperature abnormalities.

You might want to consider an impeller replacement just for good maintenance and peace of mind.

Yes, raw water pump, wasn't sure which was which, that's why I described location just in case I was wrong.

The impeller needs to be replaced anyway so that's where I will start. I am most curious whether there is some way I can easily bench test the unit. Right now the best I can come up with is hooking a garden hose up to it, closing off the output and seeing if any water comes out.

 

[Sparkinator]

Re: Need to figure out which water pump I need on OMC/Volvo

I've got a 95 5.0 (302) HU OMC. Before replacing the impeller on my raw water pump, it had a pretty good leak. I found on OMC parts schematics for the pump it showed a seal and on Volvo schematics it didn't. I figured it was worth a shot so I ordered a seal with the impeller. It didn't completely fix the leak, but now it only occasionally drips, and running in fresh water only, I can live with that.

I don't remember the part numbers for my pump, or if my scenario is applicable to your situation, but it might be worth a look.

Good luck!

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

I've got a 95 5.0 (302) HU OMC. Before replacing the impeller on my raw water pump, it had a pretty good leak. I found on OMC parts schematics for the pump it showed a seal and on Volvo schematics it didn't. I figured it was worth a shot so I ordered a seal with the impeller. It didn't completely fix the leak, but now it only occasionally drips, and running in fresh water only, I can live with that.

I don't remember the part numbers for my pump, or if my scenario is applicable to your situation, but it might be worth a look.

Good luck!

I put the pump in to see where water was coming from. It appeared to be where the shaft exits the pump housing. I was unable to figure out a decent way to fix this seal (I'm assuming this is the seal you mention).

For now, I ordered a new pump. Maybe during down time this winter I will spend some time figuring out how I can fix the old one.

FWIW my pump was part 3851623 which has been superceded about 3 times since then.

 

[Sparkinator]

Re: Need to figure out which water pump I need on OMC/Volvo

LINK

I ordered impeller, seal (#4), and gaskets (not sure from where) and it pretty much fixed my problem. I was leaking a steady stream and needed to do something about it. Now, I get an occasional drip from the pump, and can live with that.

The pump is the same part number as the pump you ordered, so it should have a new seal. My seal was melted and I'll probably have to get a new pump in the near future, but the new seal fixed it for the short term. I was just trying to avoid the cost of a new pump this year.

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

Where was #4 seal when you had the pump assembly apart? I saw no seal in that area when I had it apart. I'd love to fix up the old pump so I can have a reliable back-up.

It is not part of the impeller, I am assuming. But that is the general area water seemed to be coming from (where the shaft exits the pump housing).

 

[Sparkinator]

Re: Need to figure out which water pump I need on OMC/Volvo

The seal, on mine, was in the bottom of the pump housing, sealing the gap between the housing and the shaft.

Your old pump may not have had a seal. I don't know.

On some of the pumps I researched, I don't think they showed a seal. They must have settled on the current set up with the seal when they revised the part numbers and pump changes over the years. Just guessing.

 

[CChase86]

Re: Need to figure out which water pump I need on OMC/Volvo

Thanks for the help.

I just realized now that you have a very similar boat to mine, which makes me think my pump may be the same and I just missed something obvious. 1995 Four Winns Freedom 170 with 4.3 and SX drive.