Leaking Raw Water Pump

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ChrisL

ChrisL

Veteran Member
Joined
Jan 31, 2015
Messages
42
Location
US
Vessel Name
Morning Star
Vessel Make
Defever 41
Hi All,

I notice a small drip, but continuous drip from my starboard side raw water pump. Does the dripping mean I have to replace the impeller, pump or both?

Thanks
 

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Do you recommend to change out the impeller at the same time? Should I do both star and port at the same time or wait to it starts to leak too?
 
Great! Thank you
 
When the seal goes bad, many times it means the bearing is becoming worn. If you just change the seal, make sure the shaft is tight in its' rotation. A worn bearing will just ruin the new seal and maybe scar the shaft.
 
ChrisL said:
Do you recommend to change out the impeller at the same time? Should I do both star and port at the same time or wait to it starts to leak too?
Click to expand...

If you do a lot of cruising in out of the way places, I'd replace both pumps with new ones and rebuild one old pump to keep aboard as a spare.

Otherwise rebuild both pumps. A rebuild would include new impellers, seals, gaskets, cams and covers.

Take a look at the condition of the shafts after disassembly.

If they are well worn I'd just buy replacement pumps and again try to rebuild one as a spare.
 
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Assuming the pump is Jabsco, they are normally common and cost effective to buy new vs having an outside shop rebuild. I use the 60% rule - if the rebuild cost is more than 60% cost of new, buy new.

Also, I change out my Jabsco impellers after 18 to 24 months. The old ones come out looking pretty good. Never run to destruction, mine are pretty cheap vs a failure. Some +300 hour a year guys change them out annually.
 
Absolutely

"If you do a lot of cruising in out of the way places, I'd replace both pumps with new ones and rebuild one old pump to keep aboard as a spare."
:thumb:
 
Many have advised to "rebuild the pump". That's fine if you know how to do things like this and have the tools and equipment to do it. Some do, some do not.

The parts to rebuild the pump are not free and there is some risk of failure, either immediate or long term, if you don't do an expert job.

My point is, for some folks, replacing the pump with a new on may be the best choice. It should take under an hour.


BTW: The leak is not a sign of a worn impeller. It's a seal and possibly failed bearings and a scored shaft. Having a spare pump on board is not a bad idea provided you also carry the tools necessary to replace the pump and have the mechanical skills to do it.
 
WesK said:
Many have advised to "rebuild the pump". That's fine if you know how to do things like this and have the tools and equipment to do it. Some do, some do not.

The parts to rebuild the pump are not free and there is some risk of failure, either immediate or long term, if you don't do an expert job.

My point is, for some folks, replacing the pump with a new on may be the best choice. It should take under an hour.


BTW: The leak is not a sign of a worn impeller. It's a seal and possibly failed bearings and a scored shaft. Having a spare pump on board is not a bad idea provided you also carry the tools necessary to replace the pump and have the mechanical skills to do it.
Click to expand...

Agree and if you cant rebuild or change out a pump due to a lack of mechanical skill you best learn or reconsider traveling to far places where there may not be adequate help. Most far traveled boaters particularly power boaters are mechanical jacks of all trades related to a complicated motorized home on the water. I personally would probably hire a mechanic even though I probably could do it but might get into trouble. Now if I saw a video or helped a mechanic do it once then no problem.
 
Capt.Bill11 said:
If you do a lot of cruising in out of the way places, I'd replace both pumps with new ones and rebuild one old pump to keep aboard as a spare.

Otherwise rebuild both pumps. A rebuild would include new impellers, seals, gaskets, cams and covers.

Take a look at the condition of the shafts after disassembly.

If they are well worn I'd just buy replacement pumps and again try to rebuild one as a spare.
Click to expand...


I have never rebuilt a pump before. While I am inherently lazy, I can usually figure things out pretty well if pressed. If it was me, I would go with Capt Bill's advice and at least buy one new pump to replace the leaking one and then try to rebuild the leaking one.

As for replacing both, I would only do that if I felt that the other was about to fail. (psychic am I) However, depending on your cruising grounds, having a new spare on the boat might not be a bad idea.

I used to replace the impeller yearly on my sailboat. The impeller was inexpensive and easy to replace. Since I am cheap as well as lazy, I doubt that I will be replacing the impellers on Kinship yearly. Overkill is one thing, throwing money away is something else.
 
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dhays said:
............I used to replace the impeller yearly on my sailboat. The impeller was inexpensive and easy to replace. Since I am cheap as well as lazy, I doubt that I will be replacing the impellers on Kinship yearly. Overkill is one thing, throwing money away is something else.
Click to expand...

Your engine manufacturer will have a maintenance schedule that will dictate how often the impeller should be replaced. I would stick with that.

You might be fine going longer or your impeller might fail and small pieces of rubber end up stuck in the heat exchanger. Your choice. No guarantees either way.
 
I have rebuilt water pumps several times and also had them reuilt preofesionally. They have never lasted as long as a new pump. I would take the leaking pump one off, keep it as an emergency spare and install a new one.

As far as impellors go, we change ours annually on my schedule. It's hard to predict when they will go and I'd rather do it on my schedule, at the dock, with a cool engine room and resources available in case I screw something up. ;)
 
WesK said:
Your engine manufacturer will have a maintenance schedule that will dictate how often the impeller should be replaced. I would stick with that.

You might be fine going longer or your impeller might fail and small pieces of rubber end up stuck in the heat exchanger. Your choice. No guarantees either way.
Click to expand...


I can't recall at the moment what the recommended replacement interval is. I have looked at it before but can't recall. I just looked it up and Sherwood recommends replacing the impeller every year, so I guess I will continue to do that.
 
I have rebuilt many engines, etc, with good success. But my success rate at rebuilding water pumps with mechanical seals is POOR. Not easy to do right unless you have the right tools and a press and knowledge of how they work.

These pumps are one thing I like buying new.
 
Strongly advise keeping your pump as emergency spare (whatever that means!) and buying new from Seamax. These are a much better design than Sherwood and less expensive.
 
Chrisjs said:
Strongly advise keeping your pump as emergency spare (whatever that means!) and buying new from Seamax. These are a much better design than Sherwood and less expensive.
Click to expand...


Yes, that is something that I plan on doing when it is time to replace the pump as it is a bolt on replacement.
 
Change the impellers every year and keep the old one for a spare (for a year). Cheap insurance.
 
If you are not confident on a rebuild,then I would replace both pumps with new, thereby starting with a fresh slate with both engines, and keep the one that was good as your spare.
 
From the picture posted, the yellow paint suggests Cat engines. The belt suggest belt driven pumps. So your seals are only keeping the water from dribbling into the bilge. No biggie. I had one dribbling for about 10 years before I bought a new pump, as they were expensive and I didn't want to rebuild. The face plate was worn enough by then that it would have needed replacement too. And the cam. And the impeller. Get the idea?
If it is an inexpensive replacement, do it sooner.

A gear driven pup may also have seals on the other side, between the pump body and the sump. If those go, much more of an issue, so take the dribble as a sign that the pump should be replaced. Now.
 
I don't have anything to add on the pumps, but I just spent many hours dealing with a huge rusty mess on my current boat that was caused by salt water leaking out of impeller pumps at some point long before I owned it, and not cleaned up properly. My 2 cents is to not put off fixing the problem, and make sure to carefully clean up any salt that may have gotten on the rest of the engine after the new pumps are installed.
 
Mine was leaking badly on sea trials when I bought the boat. So when hauled out I just told the yard, new pump. Later I found both a rebuilt and a NEW pump already stashed on the boat! Plus a dozen or so half worn impellors, lol.
 
My JD's use a Johnson pump. I had a leak on starboard side engine and replaced with a new spare pump. Then I took the old pump to the dealer, who replaced the seal etc. The seal failure was unusually early in the pump's life according to the dealer. Stuff happens.

I also bought another new pump, so spares inventory is now one new pump, one rebuilt pump plus four additional spare impellers. The Manual lists raw pump as a 2000 hr/24 month service item, so I'm good to go for quite a while (touch wood).
 
Chrisjs said:
Strongly advise keeping your pump as emergency spare (whatever that means!) and buying new from Seamax. These are a much better design than Sherwood and less expensive.
Click to expand...

I wonder just buy a new pump in case of Sherwood or seamax, if they have any information about the failure of seamax or new pumps Sherwood?:nonono:

I saw this in another forum seamax, whether it is true in general or in one case?:eek:

Sherwood vs Seamax? – MV Dirona

Warning! Do not use the Seamax pumps! I learned the hard way. My sherwood pump on my cummins 6bta was going thru impellers. I replaced it with an expensive Seamax pump. After around 1000 hours the teeth on the drive gear sheared off. This damaged the gear on my cam so now I’ll need to pretty much rebuild the motor. I purchased the seamax pump from Tony Athens at Seaboard marine. It was only 15 months old and the warranty is advertised as a “no hassle 2 year warranty”. When I contacted Tony at Seaboard marine, he will not take responsibility for the pump or damage to the motor. He is coming up with all kinds of lame excuses trying to blame the installation or the cam gear. Since this happened, I have spoken with mechanics who have seen this before. It’s not worth risking your engine. It’s much better to just change impellers more often and even change out the sherwood pump occasionally
 
The Op`s pump has Jabsco in the casting. It might b e leaking but it is a very clean maybe freshly painted pump that speaks of a well maintained ER. Bet it`s a small leak, so far.
 
North Baltic,
There's nothing wrong with the Seamax pumps.
I bought one when they first came out (7or 8 years?) and other than a new impeller every year, they have been stone reliable, no breakdowns or problems.
I have since installed them in 6 other boats I have worked on, no problems with them either.
I think the person who had that problem might not be entirely up front about the circumstances.
Tony Athens is a straight shooter, a very knowledgeable mechanic, and is generous with what he knows.
He personally developed the Seamax pump to replace the notoriously fickle Sherwood pumps on the Cummins B and C motors, in order to provide his customers with a reliable pump.
If you're going to spread second hand crap about him around here, there's gonna be a fight...
 
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