Deep gouges inside my water pump

[Presentation]

Deep gouges inside my water pump

Anyone else having this issue?

Note: I have twin 5.0L V8 Mercs with Bravo III’s circa 2003. I'm just under 400 hours.

I had my mechanic change my impellers. He showed me something. With the water pump open so I could see the brass inside part of the water pump where the impeller spins around there were deep gouges on both sides. I would estimate the groves were more then 1/16” on each side, 1/8” total. He said the groves are bad enough that he is concerned with slow speed overheating due to loss of the seal on each side.

He said in earlier years there was a small plate inside the water pumps that you could replace.

The cost of a new water pump is $350 each. Both of my water pumps have this issue.

Here is the kicker. He told me this was the third boat that he saw this, all this year.

He also told me he has heard about this issue from other mechanics recently.

We jointly decided to change the impellers and reinstall as is. I will keep a close eye on the water temp at slow speeds. I am a high hour boater, 150+/year so I should change the impellers every year or two at the most. I plan to have this done again next year and see if the issue has progressed.

Again, anyone else having this issue?

 

[Dave S]

I guess I don't quite understand where the gouges were. I had read a posting on another board awhile back where someone was talking about a gouge on the backing plate inside the brass pump itself. If it's on the circumference of the round surface were the impellers also damaged?

I have also been told by my dealer that the life of an impeller is generally longer with the brass pumps than with the plastic ones. They recommend 100 hours for the plastic ones but say the impellers in the brass pumps are good for about 300 hours.

 

[keokie]

I'm not positive, but I am pretty sure you have the same pumps my 496's have. They are junk. The housing is too soft so they wear very quickly. The pump on my 502 is much better (and way cheaper at about $75). Your mechanic is right to be concerned about the sealing problem, and it will only get worse. Watch your temps. I know of some blown motors due to these pumps.

I know a machine shop that makes a kit for these. It includes a stainless (or in my case inconel) wear plate for each side, as well as the appropriate spacers to make the pump fit back together correctly. This will very greatly increase the life of the pump. They are not cheap, but pay for themselves very quickly.

 

[Presentation]

I know a machine shop that makes a kit for these. It includes a stainless (or in my case inconel) wear plate for each side, as well as the appropriate spacers to make the pump fit back together correctly. This will very greatly increase the life of the pump. They are not cheap, but pay for themselves very quickly.

Thank you. Do you have a website or contact information?

 

[Presentation]

I guess I don't quite understand where the gouges were. I had read a posting on another board awhile back where someone was talking about a gouge on the backing plate inside the brass pump itself. If it's on the circumference of the round surface were the impellers also damaged?

I will try to explain this better.

Picture the impeller.

Lets pretend it’s a car tire.

The part of the car tire that would touch the road is one area where the impeller would touch the brass insides of the water pump. This area has no damage.

Now picture the car tire side walls. The part where the impeller touches the brass insides of the water pump on the “side walls” has the deep gouges.

Per the mechanic, older boats have backing plates between the impeller side walls and the water pump that you can replace. You get wear; replace the inexpensive backing plate, good as new.

The brand new boats may have this design but with less wear its not yet noticed. Older boats have the backing plates so no issue.


Again, the mechanic has seen this 3 times, all recently, all same issue.

 

[sbw1]

Crusader 496s now have redesigned water pumps due to the originals failing. Failures occurred around 300 hours. I replaced both of mine. Unfortunately, Crusader considers water pumps to be "wear items" and they were not covered under the warranty. I suspect the mercs are no better.

 

[RollerCoastr]

Let me get this straight... The miserable @%$#ing water pumps I've been fighting all these years were replaced with a WORSE design?

I have the older, "3 peice" units with a wear plate on each side. The wear plates are thick enough that if I don't have a new one on hand, they can be flipped over and re-used. I wouldn't consider NOT replacing or reversing it, so I don't understand why they would re-design the pump and omit the plate.

What am I missing?

 

[Dave S]

Doug

Thanks for the detailed explanation. I believe that is exactly the way I remember the problem being described on the previous thread I mentioned that I saw on another board. Was any theory offered on what causes this wear?

If you get the information on the Stainless Steel kit that fellow is making, please post that information here. I am sure others will want to go that route also if faced with the same problem. In the meantime, I will also ask my dealer what their experience has been with these newer brass pumps. I would also think if the problem is widespread enough that eventually Merc will be forced to come up with a fix but I am not holding my breath.

Dave

 

[fc3]

Jabsco sold a replacement raw water pump for Merc engines. It would not fit engines with the serpentine belt however. Maybe they revised it? Jabsco makes good pumps. Merc just makes money -- by selling junk.

Best regards,
Frank C.

 

[Dave S]

Jabsco sold a replacement raw water pump for Merc engines. It would not fit engines with the serpentine belt however. Maybe they revised it? Jabsco makes good pumps. Merc just makes money -- by selling junk.

Best regards,
Frank C.

Tell us how you really feel Frank.........just kidding.:smt043:smt043

Maybe Doug can tell us if his pump is labled "Mercury" or if it is from another supplier and if so who that supplier is.

Dave

 

[Presentation]

The pump was Original OEM. All black like the engine. I did not see a label but I did not look for one either.

 

[Skuza]

I recall chaging ours and the wear you describe. I thought I remember a brass wear plate but I'm not sure. I too was concerned about the gouges. We changed one complete pump and the impeller on the other. Have not noticed any difference in temp in the 3 years of running. This year will be time for preventative maintenance so we will change the impellers. I will have to rememeber to pay attention if there is a wear plate included.

 

[keokie]

I will contact the guy that made the plates for mine and get the specifics if any of you are interested. Those gouges really do cause the pumps to fail. Merc even mentions it in the service manual.

 

[Dave S]

I will contact the guy that made the plates for mine and get the specifics if any of you are interested. Those gouges really do cause the pumps to fail. Merc even mentions it in the service manual.

Please do that and post it back here. I would also be interested in how the end to end tolerances for the impeller are maintained if he adds extra thickness thru the use of a plate. Would that not cause a "too tight" situation?:huh:

 

[Presentation]

I will contact the guy that made the plates for mine and get the specifics if any of you are interested. Those gouges really do cause the pumps to fail. Merc even mentions it in the service manual.

I am very interested.

Thank you for your offer to help.

 

[keokie]

Yes, the wear plates do require the use of custom spacers to return the impeller clearance to factory. I'll report back on specifics.

 

[Salty Dog - LI]

Unfortunately, the water pump housings and impellers will wear over time, due to friction and sand grit being sucked through the engine. Rubber impellers should usually be replaced every 2-3 years to be safe. The pump housings should be inspected for wear and replaced if needed. If there are deep gouges in the housing body, then the housing should be replaced as well. On Merc engines with Bravo drives, the belt driven water pump housings that are made out of plastic don't last as long as metal ones. They will wear and have to be replaced eventually. The rubber impeller blades have to rub against the housing and seal well to get maximum suction and water flow. For my Merc 454 with Bravo I drive, my water pump housing is plastic. The water pump kit (housing, impeller, and stainless wear plate) costs $100. I end up replacing the whole unit every 3 years so I have no overheating problems during the season!

 

[fc3]

I ran into a guy from Jabsco at the boat show this weekend. We chatted about Merc raw water pumps. He agreed that Jabsco is missing one heck of a big opportunity by not having a retrofit pump to replace Merc's junk pumps. He was going to take the idea back to the factory. Let's hope something comes of it.

Best regards,
Frank C

 

[keokie]

Sorry to take so long to get back. I tried to visit the company that did my pumps, but was unavailable. Anyway, you can contact Bergeron Engineering in Mesa, AZ. The number is 480 834-1531. Ask for Phil or Craig. They will remember the pumps they did for my 310. If not, my name is Chris, they'll definitely know the boats in my sig.

They are a small, but very busy company so it may take a few attempts to get them. I have no affiliation, but I have been a customer of theirs for at least a dozen years.