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Old 18-01-2020, 15:04   #1
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Raw water pump - Ouch!

My water pump">raw water pump had a small leak for a while. After a long layup the leak got a bit worse when relaunched, and water started appearing in the oil. Ripped the pump off the engine and the image shows what was underneath

The lesson learnt is replace that leaky water pump seal ASAP. Don't assume the oil seal is still fine.
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Old 18-01-2020, 16:11   #2
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Re: Raw water pump - Ouch!

Oooh yes that's ugly,
A safer cooling system design is having a belt drive off the block water pump IMO though not as pretty of course. Especially true when salt water is the coolant
Good on you for posting the warning.
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Old 18-01-2020, 17:18   #3
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Re: Raw water pump - Ouch!

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Originally Posted by Compass790 View Post
Oooh yes that's ugly,
A safer cooling system design is having a belt drive off the block water pump IMO though not as pretty of course. Especially true when salt water is the coolant
Good on you for posting the warning.

Thanks! One saving grace is that the PTO gear driving the pump is an optional add on for the engine, so removal is easy enough - providing that horrible rusty bearing shell can be popped out of the alloy housing!!


Though if one talks about cascading failures, I'm now sure that this leak caused condensation to form on the "mist lubricated" injector pump which caused the fuel rack to jam which in turn caused the engine to rev well past high idle (and not shut down either until something was held over the air intake) within a couple of turns on the starter after a 12 month or so period of not being started which in turn caused the rear main crankshaft seal to chew out and start leaking.


So a few boat bucks will be in order to fix what would have been a relatively simple if nipped in the bud.
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Old 18-01-2020, 17:39   #4
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Re: Raw water pump - Ouch!

Though if one talks about cascading failures, I'm now sure that this leak caused condensation to form on the "mist lubricated" injector pump which caused the fuel rack to jam which in turn caused the engine to rev well past high idle (and not shut down either until something was held over the air intake) within a couple of turns on the starter after a 12 month or so period of not being started which in turn caused the rear main crankshaft seal to chew out and start leaking.


So a few boat bucks will be in order to fix what would have been a relatively simple if nipped in the bud. [/QUOTE]

Lots of penetrating oil & freezing spray or heat + puller should get the bearing out.

Yes I'm sure you are right about the injection pump. It doesnt take much to interfere with the fuel rack movement plus those rust flakes will wear the plunger drive parts. What model engine is it?

I feel your pain as deferred engine work has cost me a lot as well but even worse was I got advice from a well regarded diesel " mechanic" that lead me astray.
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Old 18-01-2020, 18:21   #5
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Re: Raw water pump - Ouch!

Quote:
Originally Posted by Compass790 View Post
Though if one talks about cascading failures, I'm now sure that this leak caused condensation to form on the "mist lubricated" injector pump which caused the fuel rack to jam which in turn caused the engine to rev well past high idle (and not shut down either until something was held over the air intake) within a couple of turns on the starter after a 12 month or so period of not being started which in turn caused the rear main crankshaft seal to chew out and start leaking.


So a few boat bucks will be in order to fix what would have been a relatively simple if nipped in the bud.
Lots of penetrating oil & freezing spray or heat + puller should get the bearing out.

Yes I'm sure you are right about the injection pump. It doesnt take much to interfere with the fuel rack movement plus those rust flakes will wear the plunger drive parts. What model engine is it?

I feel your pain as deferred engine work has cost me a lot as well but even worse was I got advice from a well regarded diesel " mechanic" that lead me astray.[/QUOTE]


The engine is a 3 cyl Mitsubishi, which isn't a bad engine as it's certainly been put through torture by the installer, the PO and now me(!) and yet runs sweet enough (and starts in the shortest amount of time I've ever seen a diesel start). It's main problem is it's spent more of it's life laid up (long story) and has seen little service use (It's 9 yo and less than 200 hours).
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Old 18-01-2020, 18:47   #6
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Re: Raw water pump - Ouch!

Well if it's an easy starter it sounds worth saving especially with the low hours. Yep lack of use in salt air is a killer. I expect you can get non "marine" parts for it as well which is really helpful. A friend really liked his Mitsi twin marinised by Vetus.
After looking at your pic the bearing removal looks problematic as the shaft is sitting in it.
Good luck
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Old 18-01-2020, 19:04   #7
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Re: Raw water pump - Ouch!

Ah, the gear and shaft are attached to a plate that is unbolted from the rear of the timing cover ( boy, was I glad to discover that). Fortunately the pto gear is optional and was obviously designed for field installation. It's just the rusted bearing that, hopefully, will be the only challenge (on this job at least).
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Old 19-01-2020, 11:38   #8
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Re: Raw water pump - Ouch!

As a long time boater and family who owed a marina / boat sales and service shop and then traveled the Bahamas on my boat with a friend who owned a boat service shop one of the things I learned is that little problems only become big ones.
Especially it was taught to me to develop a critical eye and not just a casual eye when looking over boating systems.
Forget the “it it ain’t broke don’t fix it” old saying.

Essentially take everything apart and put back together on a rotating basis (electronics excluded). Not all on the same schedule but depending on critical nature of system and it’s exposure to heat/salt water/electricity it pretty much all gets disassembled, cleaned, lubed and reassembled whether broken or not. Helps to keep a log as well.

Even with that things still happen occasionally that are unexpected. I realize that sailboats are less dependent on their mechanical systems and are often considered the “ugly step sisters” of the boat - are often very inaccessible ( once again because they are secondary) so easily ignored until they fail.
Even though engine may only be needed a small portion of the hours a boat is moving they are often at critical times.

Start at the bow and work your way to the stern - then repeat.
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Old 19-01-2020, 12:47   #9
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Re: Raw water pump - Ouch!

My raw water and fuel pumps driven off a single drive from the Vetus engine's power takeoff failed within two years and wrecked both pumps and allowed water into the crank case. Ripped the this system out, placed a plate and gasket over the power takeoff opening, attached a Jabsco belt-driving pump on a homemade mounting bracket driven by a belt from a second crankshaft pulley and installed a VW electric fuel pump. Had to replace the Jabsco raw-water pump and VW type fuel pump once each in thirty years. Originally $1$ for the VW pump which is now available for diesel but the old gas one worked just fine.
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Old 19-01-2020, 17:25   #10
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Re: Raw water pump - Ouch!

I really don't know why the vast majority of pleasure boats use heat exchangers (with their associated salt water pumps) for engine cooling. Reading this forum, and from many other sources, they seem to be nothing but trouble. Around here there are a great many fishboats and small tugs in the same size range as your average sailboat these days and I can't say I've ever seen one of them with a heat exchanger setup. They all, like Scorpius, use keel coolers. Just run some kind of pipe along the outside of the hull, run the freshwater engine coolant through it, and Bob's your uncle: simple and keeps salt water WELL away from the engine - which has to be a good thing.

Of course you then need a dry exhaust. I'm on my second automotive (small truck) muffler in 35 years. I'm not sure what it cost me but I don't think it was more than fifty bucks - fifteen years ago.
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Old 19-01-2020, 18:36   #11
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Re: Raw water pump - Ouch!

That belt driven pump idea sure sounds good. It's got to be much better than relying on a two dollar seal to keep the ocean out of the engine! And I've thought of keel cooling / dry exhaust but that would turn most sailboats into ovens, especially mine


Anyway, the PTO gear came out easier than expected and aside from the front bearing is serviceable. No doubt salt water has been splashing around the gears but the engine oil has helped protect stuff. Surprising, the rear bearing of the gear also had sea water damage to, but nothing like the front one. The pump bearing was absolutely toast. Here's what's left of the it...
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Old 19-01-2020, 20:11   #12
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Re: Raw water pump - Ouch!

Quote:
Originally Posted by Scorpius View Post
I really don't know why the vast majority of pleasure boats use heat exchangers (with their associated salt water pumps) for engine cooling. Reading this forum, and from many other sources, they seem to be nothing but trouble. Around here there are a great many fishboats and small tugs in the same size range as your average sailboat these days and I can't say I've ever seen one of them with a heat exchanger setup. They all, like Scorpius, use keel coolers. Just run some kind of pipe along the outside of the hull, run the freshwater engine coolant through it, and Bob's your uncle: simple and keeps salt water WELL away from the engine - which has to be a good thing.

Of course you then need a dry exhaust. I'm on my second automotive (small truck) muffler in 35 years. I'm not sure what it cost me but I don't think it was more than fifty bucks - fifteen years ago.
NOISE
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Old 19-01-2020, 23:04   #13
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Re: Raw water pump - Ouch!

Not to mention that steel, at least at earth-bound ambient temperatures, isn't flammable, so for anyone with a wood or plastic or aluminum boat, the 'inconveniences' of a heat-exchanged engine far outweigh the benefits derived from a keel-cooled system.
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Old 19-01-2020, 23:31   #14
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Re: Raw water pump - Ouch!

Quote:
Originally Posted by Reefmagnet View Post
That belt driven pump idea sure sounds good. It's got to be much better than relying on a two dollar seal to keep the ocean out of the engine! And I've thought of keel cooling / dry exhaust but that would turn most sailboats into ovens, especially mine


Anyway, the PTO gear came out easier than expected and aside from the front bearing is serviceable. No doubt salt water has been splashing around the gears but the engine oil has helped protect stuff. Surprising, the rear bearing of the gear also had sea water damage to, but nothing like the front one. The pump bearing was absolutely toast. Here's what's left of the it...
I had a pump bearing seize up in a shaft of a direct driven pump and the first symptom was the engine appeared to be seized.

Took awhile to realise the seized bearing in the pump was the thing that was stopping the engine turning over

However it seems to me that pros and cons of both external belt driven and internal direct driven pumps are about the same. Both give problems, just different problems.

A dry exhaust is in general more problematic than raw water cooling in a sailboat. IMO. Sometimes I think that keel cooling and raw water pump just for a wet exhaust could be the best of bad alternatives.
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Old 19-01-2020, 23:53   #15
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Re: Raw water pump - Ouch!

Also, don't know what bearing was in the pump before, but a call to the bearing house to get the highest quality fully sealed bearing to replace the old one might help forestall this in the future. Same for the bearing in the drive end, though it might be better to have it sealed on the pump side only...if that's not available, you can always just pry the engine-side seal out.
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