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-   -   Raw Water Cooling - No Water Coming Out (http://www.sailnet.com/forums/gear-maintenance/45231-raw-water-cooling-no-water-coming-out.html)

montenido 07-22-2008 08:22 PM

Raw Water Cooling - No Water Coming Out
 
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

deniseO30 07-22-2008 10:48 PM

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!

SteveInMD 07-22-2008 11:32 PM

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.

beej67 07-23-2008 12:39 PM

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.

RAGTIMEDON 07-23-2008 01:30 PM

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!

beej67 07-23-2008 04:40 PM

Quote:

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

ahmetb 07-23-2008 06:02 PM

If it is a universal, with pencil zincs, it is a very good chance that it is the heat exchanger.
Ahmet

Spiritman 07-23-2008 07:04 PM

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.

saurav16 07-24-2008 11:26 AM

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...

timebandit 07-24-2008 12:40 PM

Beej67 is almost right:eek:

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

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

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

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

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:


Quote:

Originally Posted by beej67 (Post 344932)
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.



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