Buggered Impeller.

[Cigatoo]

If you cannot find thumbscrews, plastic-headed or metal, a better replacement would be allen-heads rather than slotted head screws. Those slotted-head screws are easily forever lost in a bilge when working on a pump in a difficult location.

What he said plus add 2 studs with wing nuts and and lock washers at the top of the pump to hang the gasket on when assembling. Stainless of course. I made my own studs by cutting the heads of of screws.

 

[firehoser75]

Gotta love the Borel alarms. I am going to be putting them in our new boat this winter.

Totally agree. Coming from a sailboat with the engine raw water splashing "noisily" and visibly right beside where I sat steering the boat in the cockpit, and moving to our Nordic Tug 37 where the exhaust water exited the boat a few feet inside the stern and totally underwater (and therefore you could not easily see it, if at all), I added 2 alarms.

I added an Aqualarm flow alarm between the raw water stainer and the pump. This alarm will sound if you forget to open the through hull, something blocks your through hull or strainer, the pump "fails" or malfunctions, or any other reason the water flow is greatly reduced. If nothing else, it could save a person from those "brain farts" where the through hull was left closed and the impeller was destroyed and then the "fun" work of finding all of the missing pieces !
The other alarm I installed was the Borel exhaust hose overheat alarm. As others have alluded to, this is the location where an overheat will first show up, and the Borel will provide early warning to prevent the damage that is often caused before the "regular" or "normal" high temp alarm sounds! Aqualarm makes one too, but the Borel gives an earlier (lower temp) alarm. In my case, the Borel alarm saved my bacon (in a sense). Unknown to me, my exhaust elbow (that I had decided could wait a year before I replaced it after purchasing the boat (14 years old at the time)) had corroded through on the inside (even though on the exterior it looked basically brand new) and was not providing a full "cooling spray" pattern so my exhaust hose had 2 "hot spots". Without this alarm, I could have made a terrible mistake and decided that the elbow could go for a few more years completely unaware of the potential damage this could create. The hot spots, upon my investigation due to the alarm, showed hot enough to eventually delaminate the hose maybe causing an internal blockage resulting in a damaging overheat, or the hose may have developed a leak or large sudden failure and pump hot saltwater into my bilge along with poisonous exhaust gases! Also, due to the elbow being "double jacketed" with the exhaust water injected right up by the turbo, this corrosion could have allowed saltwater to get into the turbo or even the exhaust side of the engine itself causing major (very expensive) problems!
Yes, I describe the worst outcomes, but I wanted to be best equipped to avoid and prevent issues. Both of these alarms and the small panel that sounds and shows the alarm location were very inexpensive as far as "boat expenses" go (around $300 for all). Installation was not difficult but could vary by boat and setup. Very cheap insurance in my opinion, and I highly recommend them. No affiliation with either company, just a customer.
I had a speed seal on my sailboat and loved it! Very easy to use. Too bad they went out of business.

 

[Marco Flamingo]

I didn't look for an off-the-shelf system, just built my own. $3 for a NO temperature sensor (75C)and $1.50 for a buzzer/LED light. I probably could have gone with a 60C temp sensor. The wire and 3 amp fuse was left by the prior owner. Since I don't have twin engines, if the buzzer goes off I know "which engine" isn't getting sufficient raw water. Took less than an hour to install by running the exhaust sensor wire back up the transmission cable to the helm.

I did buy 2 temp switches, therefore I could have a dual duty light/buzzer that also sensed a coolant circulation failure. If the coolant system drained or failed because of the pump, where would an aftermarket temp sensor be attached to quickly sense an overheat? If I used the same buzzer for both temp sensors, I don't think that I would need to know immediately whether the overheat was because of a lack of raw water or a lack of coolant. Shutting down would be the important first response. If the exhaust is hot, it's raw water. If not, it's a coolant issue. Diagnosis complete and on to remediation. It would raise the cost of my system by an additional $3.

 

[Slowmo]

I'd buy a new pump AND rebuild this one as a spare. When I had a single engine water pump failure was one of the things that happened from time to time. Generally it was shaft seal leakage that killed mine but more than once I've had to swap pumps in some anchorage and be thankful I had one ready to go. Even with my twins I carry a spare raw water pump. It's priceless when you need it.

 

[Dougcole]

When I opened my pump on my "new to me" boat, the impeller was as battered as yours

I also found one screw was completely rotted away at the threads and a couple of the others were flat head types, probably original that had the screw-heads buggered up such that the screwdriver would slip either unscrewing or screwing-on depending on how the screwdriver was mishandled

I managed to use a hacksaw to renew the screw-heads as best as I could, but I was thinking of replacing them with Allen-head cap screws. I never thought of thumb screws. I would be concerned of not being able to compress the screw tight enough to prevent any water-pump leaks from the cover. Or worse, the plastic part of those thumb-screws breaking off leaving the cover loose.
So let us know how those thumbscrews work out for you. I would be willing to try it but I am still leaning toward socket heads.

Unfortunately, that pump is likely due for a rebuild.



I had that same issue on my boat on one pump not too long after I bought it, except one of the screws sheared off flush. I took it into my local parts guy to see if he had any advice. He said to send it off to depco for a full rebuild, which is what I did with both pumps. They got the old screws out and replaced them with bolts, which I much prefer. I think it was around $250 per pump, but they were like brand new when I got them back.


The thumb screws would be nice, but I have to pull my pumps to change the impellers anyway, so not much point.

 

[BruceK]

If the impeller plate shows wear, is there a reason not to flip it over, using the "outside" surface inside?

 

[Max1]

I didn't look for an off-the-shelf system, just built my own. $3 for a NO temperature sensor (75C)and $1.50 for a buzzer/LED light. I probably could have gone with a 60C temp sensor. The wire and 3 amp fuse was left by the prior owner. Since I don't have twin engines, if the buzzer goes off I know "which engine" isn't getting sufficient raw water. Took less than an hour to install by running the exhaust sensor wire back up the transmission cable to the helm.

I did buy 2 temp switches, therefore I could have a dual duty light/buzzer that also sensed a coolant circulation failure. If the coolant system drained or failed because of the pump, where would an aftermarket temp sensor be attached to quickly sense an overheat? If I used the same buzzer for both temp sensors, I don't think that I would need to know immediately whether the overheat was because of a lack of raw water or a lack of coolant. Shutting down would be the important first response. If the exhaust is hot, it's raw water. If not, it's a coolant issue. Diagnosis complete and on to remediation. It would raise the cost of my system by an additional $3.

Interesting. I would like to do that as well.
Where did you locate the sensor?
Pictures??

 

[Tator]

"I had that same issue on my boat on one pump not too long after I bought it, except one of the screws sheared off flush. I took it into my local parts guy to see if he had any advice. He said to send it off to depco for a full rebuild, which is what I did with both pumps. They got the old screws out and replaced them with bolts, which I much prefer. I think it was around $250 per pump, but they were like brand new when I got them back."

My new Jabsco pump had one of the brass screws deteriorate and break off after one year and 200hrs. I usually replace them with SS, but thought they would last a bit longer than that. I think the quality of the metal in the screws can vary. I don't think it necessarily means you need a rebuild.

Tator

 

[Marco Flamingo]

So let us know how those thumbscrews work out for you. I would be willing to try it but I am still leaning toward socket heads.

I could only get them finger-tight enough for a very slow drip. Had to use pliers for the last quarter turn. It was still easier than getting a slot screwdriver in there, but probably not as easy as an allen wrench. A rachetting allen wrench would be even better, but my goal was to have something that didn't require looking for tools. I'll need pliers to remove these and then look for something like a SS wing bolt that can provide more leverage.

 

[Marco Flamingo]

Here's the install.

Max1,

The temp sensor I used is linked in my prior post. It is a "normally open" sensor that is available in Amazon in a range of temperatures. The sensor is simply attached to your exhaust system using a SS hose clamp. Mine is attached to a stainless steel exhaust riser just after the raw water enters. As long as the raw water is flowing good, the temp doesn't come anywhere near 75C (167F). If the impeller starts to fail or a heat exchanger is getting plugged, the alarm will kick off before the exhaust hose cooks. You might use an infrared heat gun on the area where you intend to put the sensor to get an idea of which temp sensor to buy. I can put my hand on the stainless exhaust pipe below my raw water inlet, so I could have gone with a lower temp sensor.

These temp sensors come with a thin silicone rubber boot over them. If you attach them to grounded metal, you must leave the boot on or else you will have a dead short (ask me how I know). The light/buzzer that I used was this size because I had that size hole in the instrument cluster from something that had been removed in the past. Again, lots of choices on Amazon for these buzzers. It is powered by connection to the ignition and I put in a little fuse.

 

[rgano]

Snazzy!