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Raw Water Cooling - No Water Coming Out

7K views 20 replies 12 participants last post by  jasongael 
#1 ·
Hi all, it has been a while since I posted, but I have been very busy fixing up Sundance. My latest venture involves the cooling system. It emitted very little water out the exhaust port before my intervention. Today I cleaned the sea water filter and changed the impeller on my water pump. I also used some rigid cable to ream out some cooling lines to insure that there were no restrictions. Well I must have knocked something loose which then lodged somewhere else because I now get NO water out of my exhaust. Believe me, I disassembled the water pump several times to insure that it was put together correctly and that it was pumping water - yes on both counts. I disconnected various water hoses and used a air pump for my inflatable to see if they were clear. All were clear except the one leading to the wet exhaust nipple. So, water goes in but does not come out the exhaust. Help! I am tired and could use some advice. BTW, I am very mechanical, just a bit stumped here:confused: .

Thanks, montenido
 
#2 ·
not knowing what pump you have I'm guessing here. I know some C30s had universal diesels. did you use the right gasket for the pump? Mine wouldn't prime or pump until I got the right gasket that is very thin. Now it works like a champ. the impeller has to be very snug in the housing and the cover plate has to rub the sides of the impeller for it pump as it should. Also the little wedge in the pump the flexes the impeller can fall out of some pumps. hope this helps!
we have 5 C30s in my boat club. nice boats!
 
#3 ·
It's possible to have an exhaust riser pipe that is blocked by carbon build-up. The carbon can block the water, the exhaust, or both.

One way to isolate the water flow problem is the remove a seawater hose, direct it into a bucket, and then briefly run the motor. If you have good flow, move down stream and try again. If not move upstream. Do this until you isolate the problem. If you don't want to get seawater on anything hookup a hose or bucket of freshwater for the tests.
 
#4 · (Edited)
Before you do anything, check the 'dumbass' factor and make sure your thru hull valve is open. I've been guilty of that before. Hehe. Now, on to narrowing the problem down:


Detach the hose that goes from the heat exchanger to the mixing elbow, then start the engine for 20 seconds, maybe less. Does water come out of that hose?

If so, then your problem is in the mixing elbow.

If not, then reconnect it, and detach the hose from the raw water pump to the heat exchanger, and start the engine again. Does water come out of that hose?

If so, then your problem is in your heat exchanger.

If not, then leave it detached, close your thru hull valve, detach the hose between the raw water pump and the strainer, and stick that hose in a bucket of water. Start the engine. Does water come out the back of the pump?

If not, then the problem is in the pump. If so, then the problem is in the strainer, or between the strainer and the thru hull, or there's some gunk in the thru hull itself that's clogging it.


NOTE: do this in short bursts, while the engine's cold. Don't go and overheat your engine and then say "beej67 told me to do it!" Hehe.
 
#10 ·
Beej67 is almost right:eek:

Always remember to start at the source and work foward.:)

No water comming in -- no water going out:eek:

No fuel in the tank -- no fuel at the injectors:eek:

Low voltage in the battery -- low voltage everywhere:eek:

Don't get caught up in the, "it happened to me once and it was the---".

Trouble shooting is a step by step process and if you skip a step and you can't fix it you have to call in a pro.

AND

He is the one that plugs in your dock line and fixes your electrical problem and ONLY charges you $50 for the call:mad:

Rule one still applies.

The last thing you mucked with is the first thing to mess up.

Rick :cool:

Before you do anything, check the 'dumbass' factor and make sure your thru hull valve is open. I've been guilty of that before. Hehe. Now, on to narrowing the problem down:

Detach the hose that goes from the heat exchanger to the mixing elbow, then start the engine for 20 seconds, maybe less. Does water come out of that hose?

If so, then your problem is in the mixing elbow.

If not, then reconnect it, and detach the hose from the raw water pump to the heat exchanger, and start the engine again. Does water come out of that hose?

If so, then your problem is in your heat exchanger.

If not, then leave it detached, close your thru hull valve, detach the hose between the raw water pump and the strainer, and stick that hose in a bucket of water. Start the engine. Does water come out the back of the pump?

If not, then the problem is in the pump. If so, then the problem is in the strainer, or between the strainer and the thru hull, or there's some gunk in the thru hull itself that's clogging it.

NOTE: do this in short bursts, while the engine's cold. Don't go and overheat your engine and then say "beej67 told me to do it!" Hehe.
 
#5 · (Edited)
I believe the most common reason for lack of water flow is a clogged heat exchanger. Think about hole sizes-- water lines are generally 3/4 to 1 inch diameter, fittings are proportional. The heat exchanger is normally a honeycomb of small tubes, less than 1/4 inch diameter. Any given piece of crud going thru the lines will stop at the smallest restriction! In my own engine, my heat exchanger had several chunks of rubber in the heat exchanger, because the PO had used the same pump impeller until it disintegrated! There was a fairly new impeller in the pump when I took it apart, but my engine chronically overheated. I have no way of knowing how long those bits of rubber were in there before it clogged, but cleaning it out increased water flow dramatically, and dropped the engine temp to the normal range. It is also common that because of the cooling effect, calcium can precipitate out of the water and clog the small exchanger tubes. Soak the exchanger core in vinegar, clean with pipe cleaners. A cruising friend told me the proper protocol is to annually inspect the impeller, and if it looks new, throw it away and put in a new one. Impellers are cheap, a warped engine head (due to overheating) is expensive!
 
#6 · (Edited)
I believe the most common reason for lack of water flow is a clogged heat exchanger.
I've had the following happen to me before:

Mud in the filter
Grass in the thru hull fitting
Pipe collapsing under pressure load because it wasn't the right type of pipe
Broken impeller blades
Carbon gunk in the mixing elbow
An entire family of barnacles relocated to the interior of a pipe right before the filter housing.

I'd say I've seen a lot of problems with my raw water system, and I've done a lot of repairs and replacements in it, but I've never had a problem with my heat exchanger. In my experience, the heat exchanger itself is the least likely thing to screw up.

The only time I'd be worried about the heat exchanger is if you lost a bunch of impeller blades. It doesn't hurt to check, though. Basically, just disconnect stuff until you narrow the problem down, as I mentioned above.

edit:
I have a Yanmar 3GM30F freshwater/seawater cooled engine, which doesn't need/use zincs
 
#8 ·
Monte,

I hope your "intervention" went well. It's great that you have friends and family willing to support you through your issues.

I recently had an overheating problem with my Westerbeke which I solved by removing a large piece of zinc that had found its way into the outlet fitting on my heat exchanger. Very little water was coming out the back. It seems that sometimes the zinc can deteriorate at the base faster than it does elsewhere along its length -- leaving a rather hefty piece to float/roll around inside the unit. The piece of zinc had collected other little zinclets and all but blocked the outlet. This was almost impossible to see unless you got up close with a flashlight -- so look carefully.

Also, in searching for this culprit, I took the hose off the engine intake seacock and then opened the valve -- observing a two inch geyser of water. I then fooked the opening with a twelve gauge shotgun cleaning brush resulting in a ten inch geyser! Every little bit helps.
 
#9 · (Edited)
no one asked you this but its probably important... what kind of engine do you have? what is the make of your water pump? your engine maybe a universal but there are different models i.e. 5411, m15, etc...

Also if its the 5411 it has no heat exchanger...
 
#12 ·
Thank you everybody for the great ideas and advice. I have not yet gotten back down to the boat (my wife accuses me of being obsessed!!!!!). I will go through all the different parts of the cooling system from the sea-cock to the muffler. BTW, it is a Universal 5411. Sorry, I will include that important info in my next troubleshooting post.

Thanks again, and I will let you know how it pans out.
 
#13 ·
Re: Raw Water Cooling - Update

Hi all, just got back from the boat this afternoon. The short version is that everything works well now. The longer version is this: I used a brass high-pressure nozzle with a shutoff to pressure flow each section of the saltwater cooling system. Only felt some resistance once or twice. Knowing that everything was now clear, I reassembled the system and started the motor. After a minute or two of water coming out of the exhaust, nothing again. Damn, so I took apart the water pump for the 6th or 8th time since replacing the impeller and gasket. Everything looked fine, I even had my son crank the motor so I could be sure everything was turning correctly. Frustrated again, I pumped a solution of Oxalic acid through the block to remove rust scale, something I read about here. After flushing everything with fresh water and reinstalling the thermostat, I started the engine and what do you know, water was flowing from the exhaust port in a healthy stream. One thing that I had to do to make this happen was to restrict the bypass line that runs from the temperature sensor back to the intake side of the water pump. I will install a valve tomorrow so that I can control the flow there (I also read about doing that here). Motored all around the marina will nary a hiccup and plenty of water exiting the exhaust. So I am not sure which one thing that I did caused the improvement, maybe a little of each. Anyway, I am one happy sailor right now. :D

Thanks for the great advice everybody.
 
#17 ·
Well, mine is a Universal 5411. You are correct, there is no heat exchanger. I have an excellent impeller. The pump IS pumping water fine. It even gets up to the top little short hose before the last leg to the thermostat. BUT, water does not get through that channel to the thermostat. I have already verified water will go out if I pour it down the expellation hose from the thermostat. I just don't have water getting through that last length of the block. So, question is: how do I unclog that part? All help is welcome. :) you guys rock!
 
#19 ·
Jason, try the oxolic acid trick, it worked for me. Get some of the acid at WM or some other place. Mix it up in a 5 gallon bucket. Disconnect the bypass hose that runs from the thermostat back to the raw water filter, at the filter end. Remove the thermostat and re-install the thermo cover. Hold the unattached end of the bypass hose above the motor and insert a funnel into the hose. You are now going to slowly pour the acid solution into this hose so that it enters your motor from the top. Before adding the acid, be sure to disconnect and plug the hose that runs from your water pump outlet to the bottom of the engine. I think the acid solution, although mild, might do harm to your impeller and pump. Let the acid solution sit in your block for a while and then reattach all hoses (you can install the thermostat later, just don't forget). Make sure your cooling intake thru-hull is open and start your motor. This should work. If it doesn't, try using a tapered brass nozzle on a garden hose and insert it into the end of hose that you have detached from your water pump outlet. You may also want to pinch off the return hose so that the water pressure doesn't push everything back to your raw water strainer. If you finally get water to exit your exhaust outlet while under power, you are almost finished. Re-install your thermostat (after checking to see that it operates properly) and re-connect all the hoses. Now go and motor around a while and make sure that water is still exiting out the back of the boat. I ended up installing a plastic ball valve in my return line so that I could regulate how much water bypasses the system.

I hope this helps. Send me a PM if you need more info.
 
#20 ·
awesome! yeah, I actually read your previous post and thought the approach was great. On page 35 of the previously mentioned manual, there is a diagram. My blockage is between the Engine to Manifold Crossover Hose, and the Thermostat. Somewhere in that circlular route, I am blocked completely. I've tested every other possible flow, and they all work perfect. It's just that one spot. So, I think, taking your advice, I will disconnect one end of the crossover hose (farthest from thermo), and restrict the bypass hose, and use the nozzle trick 1st. If I can't blast it out that way, I will .. very slowly .. pour Oxalic Acid in there and wait a while. Then, start the engine and cross my fingers. :) Thanks man! Isn't it great owning a sailboat???? ARrrrrrrr!
 
#21 ·
so... story continues.. I got a tapered brass nozzle and shut off valve for my garden hose, and I clamped off the return hose (bypass), I put the nozzle into the crossover hose and connected the thermostat housing to a hose emptying into a bottle. But, i couldn't blast through that direction. So, I reversed it, putting the bottle on the crossover, and the nozzle into the thermostat housing and was able to blast it out. Then, I reversed it again, and was able to get flow. Once I flushed it a while, I put everything back together the correct way except I left the thermostat out, and started her up. She ran well and kept a good temp. A steady stream of water came out the exhaust, but not enough. Not even a steady pouring. So, I think maybe it got reblocked, and I'll need to flush it thoroughly and try again. I just don't want to use acid if I don't have to yet. I'll keep you posted! And thanks again!
 
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