# Yanmar 3GM 30 Cooling Water Mystery



## Jeff_H (Feb 26, 2000)

I am usually pretty good at diagnosing engine issues, but this one has me perplexed. For several years now I have had intermittent cooling water problems on my Yanmar 3GM 30F. It first showed up about 2 years ago as a less than usual water flow. 

I assumed a bottom growth perhaps fouled outside inlet strainer, and so had the diver carefully clean the inlet from the outside of the hull. I then cleaned out the fine strainer on the inside of the boat and back flushed the intake hose and system in case the outside cleaning snapped off some barnacle shells. 

I started the engine and all seemed like normal at idle but as I began to motor at normal speeds the water flow stopped entirely. So idled back to the dock. I figured it had to be on the inlet side of the pump since it got worse as the rpms and therefore suction increased. So I disassembled the system from the intake thruhull to the water pump, replaced the impeller, checked the hoses, cleaned out the strainer, back flushed the system, and tightened all of the house clamps and figured that this ought to solve the problem. 

It helped a little but the problem was still there, but again only as I throttled up. So I thought that it must be the hose from the strainer to the water pump which was 25 years old, has several tight turns and is pretty long. I figured the higher suction at higher RPM's was sucking the hose closed. 

So I went over to WM and bought a new hose. They happened to be out of a long enough length of wire reinforced in the correct size, and so I bought a regular non-wire-reinforced cooling water hose in the correct diameter and a length of larger diameter clear plastic hose, which I slid over the hose at the bends to keep it from sucking shut at the bends. And that worked better, but perhaps with a little less water than the engine had been pumping prior to all of this. 

I compromised by running the engine at slightly slower cruising speeds which seemed okay for that season. But then it started again last fall. So once again, I replaced the hose, this time with wire reinforced hose. I still placed the larger diameter clear plastic hose over the new hose at bends and places where abrasion might occur. 

As a further precaution I back-flushed the system, replaced the impeller again, and checked all of the hose clamps. And once completed that seemed to work better, but still a little less water at higher RPM's than it had been before all of this started. 

This weekend I started up the old Yanmar. It had not been run in about five weeks and had antifreeze in the system. On start up some scale came out with the exhaust water, which was something I had never seen before on this engine, but otherwise it looked like it was pumping water normally at idle. As soon as I increased the RPM's above around 2200 rpm, it seemed to stop pumping water again. 

At this point, I have a lot of confidence that the suction side of the system is clear and operational so I am completely baffled. In my mind, if this were a problem on the discharge side of the system, I would expect that a greater water flow would occur at higher RPM's since there is greater pressure to push it out of the system, and that the lack of water would occur at idle. 

In my mind the only downstream issue that I am even a little suspicious of is the water inlet at exhaust elbow being blocked and that the higher back-pressure at higher RPM's is somehow keeping the water from coming through the blocked orifice. 

Has anyone else ever experienced anything like this? Or does anyone have a theory about what is happening? 

Thank you,
Jeff


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## rugosa (Aug 30, 2011)

There's an article in March/April Good Old Boat by Ed Zacko with similar problem, his boiled down to sheared impeller retaining screw in water pump. As RPM increased impeller would freewheel in the water pump. Sorry, don't have link to send you.


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## single2coil (Apr 12, 2014)

Hey Jeff, I have same engine in my 34 C&C. Having mystery over heating also, did much what you have done. I read in one of our sailnet threads that had similar problem. They were in Europe, on a river, if I can recall.
Two things turned out. One was the exhaust elbow. The other was the shaft in the pump, the impeller slides over was slipping or cracked, ? not sure, they replaced the raw water pump, solved the issues. So it turned out to be two issues. I am now getting ready to replace the elbow, no use checking it, too much labor not to replace.


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## single2coil (Apr 12, 2014)

Jeff, that was the article I was referring to. Good Old Boat as Rugosa said.


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## capecodda (Oct 6, 2009)

Jeff, 

This is no more than a theory/guess???

There is something loose (impeller blade, scale, something) that when you pressurize the system pushes the loose item against a passage and partially or fully blocks it. The faster you run, the more pressure to seal up the flow. I'd look everyplace the raw water system gets narrow, like the input side of the heat exchanger, exhaust elbow, etc. This guess is based on the scale comment, and a belief that the suction side of the pump is all clear.

When's the last time you took apart heat exchanger(s) and had them cleaned or replaced? Might be worth a shot if it's been a while. Everyplace that the salt water goes is suspect.

Again, a guess. Good luck!


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## jsaronson (Dec 13, 2011)

Jeff,

Same engine here too. I'm assuming there are no leaks and the belt is not slipping. First guess - exhaust elbow. Second guess - foreign object in the system. 

Hope you get it solved!
Joel


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## Sailormon6 (May 9, 2002)

Mine also pumped water intermittently. The water pump is mounted on a bracket plate that is used to adjust the tension of the belt. I finally found that, after years of use, and after the belt tension had been readjusted repeatedly, the bracket had a dimple bent into it, where the tensioning bolt was situated. Every time I adjusted the tension on the belt, it wouldn't stay in adjustment, and the belt would loosen very slightly. This caused the belt to slip, and it would sometimes pump water, and sometimes not. The cause was that dimple in the mounting bracket. It created a "slippery" spot, that allowed the tensioning bolt to slip. I replaced the mounting bracket, and have never had the problem since.


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## sailak (Apr 15, 2007)

jsaronson said:


> Jeff,
> 
> Second guess - foreign object in the system.


I also thought of this. Something that idle flow doesn't more, higher rate flow moves it blocking flow somewhere. Admittedly a bit of a long shot.

Odd issue you're having. Good luck.


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## Jeff_H (Feb 26, 2000)

Thank you everyone for the suggestions and kind words. I like the sheered pin on the raw water pump drive. That is a good thought that had not occurred to me. I would hope that I would have noticed something like that when I replaced the impeller, but who knows, I missed simpler things in my old age. 

I have checked the belt. That was a good suggestion and was an early suspect and a good one at that. I replaced both belts during the first round of adventures since I had them off and they hadn't been replaced in a dozen years. Sailormon, I had that very same dimple (or slight fold) around the time that I replaced the seals in the raw water pump, roughly 10 years ago. I put the plate in a large vice and flattened it, roughed the surface with course sandpaper, spray painted it, and that seemed to fix the slipping belt problem. Maybe I should check that again just in case. 

The exhaust elbow is my next suspect after the slipping drive pin since its been a while since its been cleaned out. It wasn't bad last time, but I'll pull it off and pickle it in vinegar just as a precaution. I don't know why I don't suspect the heat exchanger, but for some reason that does not seem likely. 

The fresh water pump does not seem like a likely candidate for a couple reasons beyond the fact that I can't imagine how the fresh water pump failing could affect the water raw water flow at the exhaust. But also, usually when a raw water pump fails there are signs of leakage at the seals, which I did not see, and besides I replaced that perhaps 10 years ago, which was quoted as wickedly expensive until a friend said,"You know I just sold my boat that had the 3GM in it and the buyer was so nasty that I kept my boxes of spare parts. I have a brand new fresh water pump if you want it and it fits." I did and it did. 


I will let everyone know how this turns out.

Thank you all again, 

Jeff


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## Faster (Sep 13, 2005)

Does this occur hot or cold? wondering if it's something akin to your hot water taps at home 'slowing' as water heats up due to the washers expanding... a long shot/in the dark though.

Sounds like you've done what you can beyond the internal possibilities.. No impeller bits floating around and getting sucked into a blockage at higher flows?


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## bristol29 (Mar 29, 2012)

I had a similar problem with a 2GM20F. I finally installed a new mixing elbow that solved the problem. The elbow looked fine upon inspection so I plan to saw in down the middle. I need to know why.


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## Faster (Sep 13, 2005)

bristol29 said:


> I had a similar problem with a 2GM20F. I finally installed a new mixing elbow that solved the problem. The elbow looked fine upon inspection so I plan to saw in down the middle. I need to know why.


Yeah.. someone earlier mentioned increased exhaust backpressure at higher revs.. enough to block a marginal water injection path?? However an impeller pump is pretty close to a positive displacement pump that ought to push through that - it it's healthy, of course.


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## RonRelyea (Nov 18, 2009)

another possibility (just a guess) would be debris just before your heat exchanger ... at lower pressure, the junk just might be getting agitated around, but at higher rpm/water pressure, the junk gets pushed up and blocks your heat exchanger and blocks flow.


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## CapnRon47 (Jul 29, 2007)

I check the water entry elbow to the mixing elbow every year around this time. It just collects debris, not sure why it should be partial to higher rpm other than as the flow increases the water forces the particles to block the inner tube.










this is the elbow I am talking about. it enters at the top of the mixing elbow and it is where the water from the heat exchanger leaves to mix with the exhaust.










It sits at the red arrow and has a anti siphon loop between it and the heat exchanger.

Hope you find your answer, let us know when you do.

Ron


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## THEFRENCHA (Jan 26, 2003)

Had same problem with a 3ym
Good flow at low rpm but almost nothing after 2500
Flushed with phosphoric acid Lots of thread on forum
Back to normal and did not need to take anything apart
I would do that before trying anything else because even if mixing elbow is not the main problem in your case ....the flushing will still improve greatly the water circulation


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## Markwesti (Jan 1, 2013)

Mr. H to answer your question yes we have over heated , we have a 2QM Yanmar , heat ex changer . One time it was the through hull , completely salted up . Last time I don't know , but I changed raw water impeller and mixing elbow , Checked all lines for blockage , and the heat ex changer for block blockage , and now we are good in tell the next time HAHA . I suspect your problem is the heat ex changer .


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## jsaronson (Dec 13, 2011)

one other thought - slight air leak?


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## Jeff_H (Feb 26, 2000)

I have to admit there are some very creative diagnosticians here. I am leaning towards the exhaust elbow and blocked passages idea. To add to the discussion, the problem happens whether hot or cold. The only obvious controlling element is RPM. it stops pumping around above 2200 RPM and starts again below it. In gear or not does not change it. Jon, I like your idea about an air leak. I actually thought that might be the case so I took the intake hose off the pump, hooked up a garden hose to it and turned it on. I then closed the seacock. The strainer initially leaked but I was able adjust the lid bolts and that stopped. 

I really appreciate every one's thoughts on this problem. There are a lot of good suggestion here.

Jeff


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## RobGallagher (Aug 22, 2001)

I'm going with the exhaust elbow. Second guess is heat exchanger needs a good enema.

If you are not up to removing cleaning/replacing the exhaust elbow just yet, try a good vinegar soak on the raw water side. Let is soak a solid week Then see what comes out the tail pipe. That is most probably not a fix, but it might help in the short term and give you a clue as to the heat exchangers cleanliness. If, by chance, it makes things worse (by loosening scale and clogging things up) then you know you need to start taking the raw water side apart.

Best of luck to you and your exhaust


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## overbored (Oct 8, 2010)

check the exhaust hose/pipe. if there is a restriction in the exhaust it will build up pressure at higher RPM and the water pump pressure will not overcome the exhaust pressure. the raw water pump is not a positive displacement pump, it is a flexible vane pump and the pressure output is determined buy the speed and the stiffness of the vanes. the exhaust elbow can also be carboned up to the point where it causes back pressure into the raw water and stops the flow of water. do you have a waterlock that may be partly plugged. I am sure you checked the impeller key and pump cam are in place. wear in the water pump and pump faceplate, to thick of gasket material and wear on back wall of pump can reduce the pressure that the pump can develop allowing the exhaust pressure to overpower the water pump. Dirty raw water side of heat exchanger can cause a pressure drop across the HtEx, and low water pressure at the exhaust elbow allowing the exhaust to overpower the water pump pressure and stop the flow.


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## Sailormon6 (May 9, 2002)

Jeff_H said:


> To add to the discussion, the problem happens whether hot or cold. The only obvious controlling element is RPM. it stops pumping around above 2200 RPM and starts again below it.


That really sounds like a slipping water pump drive belt, Jeff. There's a lot of friction in the operation of the water pump. If the belt is slightly loose, it can slip. As engine rpms increase, it pumps more water, and that creates more resistance, which makes a slightly loose belt slip even more.

Previously you said the water pump bracket on your engine had the dimple that I described, and you straightened it in a vise. I have my doubts that it can be reliably repaired in that way. I would suggest you replace the bracket. It could be the source of the current problem, but even if it isn't, it's trouble waiting to happen.

There's another possibility along the same line. I bought a new water pump belt from a highly reputable parts supplier on the Bay and found that it slipped. They apparently didn't have the recommended belt in stock so they sold me one that had the same size loop, but the width of the belt was slightly thinner than the original belt. That meant that the belt didn't quite fit the pulleys, and it slipped. When you couple that with the slipping caused by the dimpled adjuster, it was difficult to identify the source of the problem because there wasn't just one source. There were two sources.

I would replace both the adjuster plate and the belt, and make sure you get the correct belt. I'd buy the belt from Bayshore Marine, to be sure you get the correct one. (I'd give you the part number for the correct belt, but I'm nowhere near my boat at the moment.)


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## Jeff_H (Feb 26, 2000)

Sailormon6

I had replaced the belt roughly a year and half ago with one that was from Bayshore Marine. I usually take my water pump with me when I buy parts since Yanmar used two different raw water pumps on the 3GM30's and that way I am sure of leaving with the correct parts. 

I had looked at the belt last weekend pretty carefully checking tension as a first step and it was properly tightened, and also carefully looking to see whether it slipped when I accelerated the engine while I was watching it. That said, I will check the belt for slippage again. 

Straightening the plate was very easy, and I did check it by putting a straight edge on it when I was done and it definitely was flat and straight. That does not mean that it has not warped again since, so I will check it and if its warped I will replace it this time. 

Overbored: I will check the exhaust hose when I have the exhaust elbow off. I plan to pull the engine and replace the mainseal and dripless bearing when I haul out later this spring, and it would probably make sense to replace the exhaust hose at that time. 

Thank you,
Jeff


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## RichH (Jul 10, 2000)

All good suggestions so far.

At the back end / worst case scenario, especially on 'older engines', and more especially for engines that are 'drained' for winter, etc. layup ---- the development of 'slab rust' inside the exhaust manifold.

When these manifolds are made, the cast iron as it cools in its mold forms 'stratifications' like an onion in its structure. When the manifold later begins to form internal destructive red (ferric) rust, if the red rust penetrates into/between these stratification layers in the casting the layers can be easily pushed apart as 'slabs'. If the 'slabs' become loose and fall to the bottom of the cooling passages, at higher water flow (rpm) they can become 'entrained' in the water flow and then migrate to the small nozzle exit/outlet on top the manifold and either block or partially block the flow. When shutting down the engine, the slabs will inevitably fall back to the bottom of the manifold .... until _some later time_ to be again be entrained in the flow - INTERMITTENT AND VARIABLE blockage intervals.

Assay .... (after eliminating other possible causes of the blockage) Run the engine until you have a blockage .... idle down (to about 1000-1200 rpm) and do not shut off the engine but remove the hose at the outlet of the manifold. If blocked flow, reinstall the hose .... then immediately remove the hose on the _inlet_ to the manifold; compare the approximate flow differences. If difference in flow is noted, then suspect slab rust.

Remedies: 
1. Remove and invert the manifold, push a stiff wire into the manifold water in/out and break up as many slabs as you can, then shake the residuals out of the manifold. When the manifold is dry internally, when you shake it you will hear/feel the 'slabs'. 
1a. Then, verify that you havent developed 'pin holes' between the 'water side' and gas side: block off one water nozzle, apply water pressure with a gage between a shut off valve on the water hose and the manifold: - pressurize, shut the valve, and monitor the gage for loss of pressure (pin holes!!!!) - slow loss of pressure or you SEE water in the 'gas side'. If pressure loss or water leak - new manifold.

Prevention of slab rust. 
1. Always run HELL out to the engine - a HOT engine run 'long and hard' will develop a quite protective form of 'black rust' (ferrous oxide) .... but will slowly change back to destructive red rust upon long term layup/inactivity. 
2. NEVER EVER 'drain' a cast iron engine for long term (winter) lay up or it WILL accelerate the formation internal red rust (inside the engine block too). Always fill with antifreeze mixture (that includes anti-rust compounds) for long term layup.

Universal manifolds are notorious for slab rust; but, slab rust can easily form in any cast iron engine .... thats why the USNavy hardly ever shuts down cast iron engines on 'active' ships - all to prevent 'slab rust'.

Lastly, with an engine that has developed 'slab rust' .... 'pickle' (descale) such an engine to remove carbonate scale ONLY when necessary; dont do so on a 'routine basis'. Use only 'inhibited' scale removing compounds when you do pickle - RydLyme, etc.

When all other investigations fail to find obvious causes of intermittent cooling water blockage .... check the manifold for internal 'slab rust'.

hope this helps.


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## Markwesti (Jan 1, 2013)

I just remembered this , replace thermostat .


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## overbored (Oct 8, 2010)

Markwesti said:


> I just remembered this , replace thermostat .


thermostat is not in the raw water


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## Markwesti (Jan 1, 2013)

overbored said:


> thermostat is not in the raw water


You are so right , but it's a good idea to change it anyway .


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## PitApe (Feb 28, 2015)

This sounds like scale build-up. The exhaust elbow is the most likely suspect, but you can get scale just about anywhere in the raw water system. I would open up the raw water system at every point you can and look for scale and/or other debris. You might well find something like this:


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## CapnRon47 (Jul 29, 2007)

All these comments are valid. I know last year when I overheated I went thru the engine cooling system looking for problems. I never found any, it was torn, but not broken, impeller that looked ok in the pump, but was very weak. Anyway, in the process, I made up an adapter set of hoses to garden hoses that I used to flush each individual element. I eventually opened up the heat exchanger (same engine, 20 years old) and while it was not pristine it was not blocked at all. I now have spare pump and bracket, trying to change the impeller with the screws on the wrong side of the pump is a real pain. I just pull the whole thing and replace it, then rebuild the old one.

good luck,
Ron


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## Jeff_H (Feb 26, 2000)

So I started working on the engine tonight. Those of you who suspected the mixing elbow, you guessed right but not for any of the reasons anyone guessed. When I pulled the elbow out it did not resemble the elbows I had seen. Most that I had seen were either heavy double wall castings that the water entered from the top or side, or else a spit tube which sprayed water into a U shaped elbow. 

This was a comparatively light weldment. There was an inside pipe welded to the flange that bolts to the exhaust manifold. Then there is an outside tube also welded to the flange, and to which the exhaust hose clamps. As designed, the water is pumped between the two pipes and flows out the back. 

When I opened the system, the inner pipe was no longer welded to the flange and was floating loose inside the elbow. I assume this is the cause of the problem even if I don't know why

The inside of the elbow and inner pipe was free of carbon build up or scale. I could slide a finger into the exhaust manifold and exhaust port and both were comparatively free of carbon build up as well. The inside of the exhaust hose was also free of scale and carbon build up. 

So tomorrow I will buy a new exhaust gasket, new mixing elbow, and length of 1 3/4 inch exhaust hose. Hopefully that's will solve whatever is troubling the cooling water system. 

Thanks everyone,
Jeff


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## jsaronson (Dec 13, 2011)

Glad you could find it and fix it!


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## RobGallagher (Aug 22, 2001)

Sounds like a winner! Keep us posted...


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## Capt Len (Oct 9, 2011)

' There was an inside pipe welded to the flange that bolts to the exhaust manifold.'If that weld should leak, what keeps cooling water from entering the manifold?


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## MedSailor (Mar 30, 2008)

Ouch! So at higher wxhaust pressure the (now free floating) internal part of the elbow would be forced into a position to block water entry from the mixing port.

Great case!

While solved, another thing to consider with similar scenarios is a WELL lubed seacock vibrating closed at higher rpm. Had that start to happen on my sea trial last week. So strange since the seacocks are usually so stiff!


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## Jeff_H (Feb 26, 2000)

Capt Len said:


> ' There was an inside pipe welded to the flange that bolts to the exhaust manifold.'If that weld should leak, what keeps cooling water from entering the manifold?


Len,

That is just what I was thinking after I took the elbow off and saw that the weld was completely missing. The water inlet to the elbow is only a couple inches from the flange and I was thinking that I was lucky that I never had hydro lock.

The only thing that keeps the water from going back into the exhaust manifold is that the gasses escaping from the engine turning over would blow the water back toward the exhaust hose which then slopes downward towards the water lift muffler.

Still and all, it was a relief to find a potential source of the problem while I was counting my lucky stars that it never overheated or got hydro locked.

Frankly, all things considered, it all went about as well as it could have. I actually snapped the head off of one of the retaining bolts (the other three came out like they had been put in just yesterday). I was really afraid that it was boring bar and tap tool time. But with the flange off there was a pretty long stub of the bolt exposed. I was able to put liquid wrench on both sides of the bolt and then it turned out with a vise grip like it was meant to work that way.

The other thing that surprised me was that before yesterday I was certain that I had taken this mixing elbow off and replaced the exhaust piping. But when I actually saw the elbow, I realized that I had not taken it off and that the hose that I replaced ran from the muffler to the thru-hull and not from the elbow to the muffler. The elbow and hose to the muffler all looked to be original to the 1996 engine.

Jeff


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## AirborneSF (Dec 14, 2010)

I have a friend who use to use 'Liquid Plummer' in his eng. let it set overnight, flush, got rid of block scale. He did have good water flow. Have NOT tried it myself yet. 02


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## Jeff_H (Feb 26, 2000)

The engine is back together with a new mixing elbow and a new length of exhaust hose. I ran the engine in the slip and all seems pretty good no matter what rpm. Of course the real test will come underway. 

I will probably pickle the system just in case. 

Thanks folks,
Jeff


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## Sailormon6 (May 9, 2002)

This thread makes me really glad I replaced my mixing elbow last year. At the time I thought, "Maybe it's not necessary. It's only 15 years old."


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## aloof (Dec 21, 2014)

Why not disconnect the various hose and simply see where the problem is? Yes, a little bit of water will squirt around, which you might control with another hose to the bilge. There will not be an overheat problem in the few seconds of running to observe the flow.

On the inlet side of the pump suck water from a bucket thru a short piece of hose. 

Disconnect the hose from the heat exchanger outlet. Run the engine. See what happens, etc.


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## jemiller22 (Sep 11, 2012)

My guess is the elbow... it is notorious for clogging up. I removed mine last year and found it clogged, but also had a pinhole in the inside of the elbow... I replaced it. it wasn't too costly and gave me some peace of mind...


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## MarkSF (Feb 21, 2011)

PitApe said:


> This sounds like scale build-up. The exhaust elbow is the most likely suspect, but you can get scale just about anywhere in the raw water system. I would open up the raw water system at every point you can and look for scale and/or other debris. You might well find something like this:


That's not scale, those are bits of old heat exchanger pencil zincs. The zincs frequently corrode through at the base, then break off.


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## Jeff_H (Feb 26, 2000)

aloof said:


> Why not disconnect the various hose and simply see where the problem is? Yes, a little bit of water will squirt around, which you might control with another hose to the bilge. There will not be an overheat problem in the few seconds of running to observe the flow.
> 
> On the inlet side of the pump suck water from a bucket thru a short piece of hose.
> 
> Disconnect the hose from the heat exchanger outlet. Run the engine. See what happens, etc.


Good suggestions. Most of that was already done before I posted the original comments. I actually have a 'Y' valve immediately behind the inlet seacock which lets me winterize my engine easily. By removing the hose from the water pump I could flush water through the strainer and out of the hull. By using the Yvalve I could suck water from a bucket and so was able to check water flow both ways and through the pump. I also disconnected the hose at the discharge end of the heat exchanger and let the water run into a bucket

By the way, its not just water that leaks, but very loud and noxious diesel exhaust when you do that, so I did not do that very long or at a high RPM.

All of that checked out fine, which is why I was mystified that with all of that seeming to function normally the water flow would stop when the engine was revved up. I had not expected to find the core of the mixing valve loose within the valve where it could shift and block the flow.

A couple other insights from this project that I would like to pass along. Yanmar claims that the mixing elbow gaskets are not reusable. Looking at how they are made, I think that they are correct so popping the mixing elbow off means having a new gasket available.

Yanmar publishes that the ID for the exhaust hose is 5 cm in diameter. That is slightly less than 2" diameter and more than 1 7/8" hose. I chose to go the 2" diameter route feeling to old to wrestle the "too small size" onto the muffler in the confined space. That led to some nervous moments tightening the hose clamps about whether it would every completely tighten up. I did have the sense to go with Tee bar type hose clamps as a 'just in case' that I was glad that I had done even if they are pricey.

Jeff


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## Faster (Sep 13, 2005)

I had a 'slightly oversized' hose for my (newly built) mixing elbow and had the same concerns, Jeff. I used a hitemp gasket sealer 'just in case'..


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## PitApe (Feb 28, 2015)

MarkSF said:


> That's not scale, those are bits of old heat exchanger pencil zincs. The zincs frequently corrode through at the base, then break off.


Yes. I know. That's why I said, "and/or other debris."


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## Capt Len (Oct 9, 2011)

That's where the bits of impeller vanes wait for your attention too. If the tranny is salt cooled more will be there too.


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