Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-05-2008, 08:34 AM   #1
Member
 
Join Date: Feb 2008
Posts: 5
Raw Water Cooling

Hello, I am looking for suggestions on what might be hanging up my raw water cooling system from flowing freely. The boat is new to me but built in the 70's and the previous owner says the water should be flowing a lot faster than what's happening, especially at higher RPM's. The engine is a DD 671 dry stacked, appears to not be over heating, and I have taken apart and cleaned the Raw Water Strainer, Heat Exchanger and replaced the impeller but still only a surge like flow. I was hoping some one could guide me on what to look at next. Thanks in advance for any suggestions. Trawler Forum has been a very positive experience and guide to my big boating success and look forward to reading it's contents nightly.

Joel Sparks
leojs is offline   Reply With Quote
Old 04-05-2008, 11:09 AM   #2
Senior Member
 
Jim Spence's Avatar
 
City: Full time cruiser
Vessel Name: Sea Eagle
Vessel Model: Californian 50' Cockpit M/V
Join Date: Oct 2007
Posts: 180
RE: Raw Water Cooling

Joel check and make sure that you don't have a hose coming apart internally. You can also dive down and make sure that the water intake is not plugged with sea life or a plastic bag.
Jim Spence is offline   Reply With Quote
Old 04-06-2008, 02:34 AM   #3
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 22,553
RE: Raw Water Cooling

I assume there is a heat exchanger , clean it.

FF
FF is offline   Reply With Quote
Old 04-06-2008, 06:04 AM   #4
KMA
Senior Member
 
City: Merritt Island
Join Date: Oct 2007
Posts: 468
RE: Raw Water Cooling

Ditto FF here. We just had ours done (8V92s), and the difference was impressive. We actually took things one step further, and had all cooling systems serviced (oil, fuel, engine, intercoolers, etc.). It's amazing how gunked up they get over time.
KMA is offline   Reply With Quote
Old 04-06-2008, 08:59 AM   #5
Member
 
Join Date: Feb 2008
Posts: 5
RE: Raw Water Cooling

Thanks guys but as I mentioned before I've cleaned the heat exchangers (engine & trans), cleaned the intake strainer and replaced the impeller. I had the boat out of the water for new bottom coat and checked the water intake, free & clear.

I was hoping their might be a common area elsewhere I should check or an insiders secret to getting the system clear. I think what's happened is some of the junk that I loosened from the heat exchanger got hung up deep in the system on an elbow or such and I probably should just go over the whole system and not be so lazy. That's what I'll do.
leojs is offline   Reply With Quote
Old 04-06-2008, 04:04 PM   #6
Senior Member
 
Join Date: Oct 2007
Posts: 138
RE: Raw Water Cooling

What kind of muffler do you have. Is it a water lift or straight through. I have the water lift on my John Deere and it surges also.
LarryW is offline   Reply With Quote
Old 04-06-2008, 05:37 PM   #7
Senior Member
 
Penta's Avatar
 
City: Sidney, BC
Vessel Name: Penta
Vessel Model: 36' 1961 Sather ex-Gill Netter
Join Date: Dec 2007
Posts: 118
RE: Raw Water Cooling

Joel - I know that this will sound silly but have you attempted to bleed air out of your system? I had this sort of problem but on a much smaller scale with our old sailboat where every time she came out for bottom paint etc the engine would run warmer than normal for weeks afterwards. Got smart one year and after she was back in the water I partially pulled the top water hose off the heat exchanger, which was the highest point in the system, and was suprized at the amount of air that came out before any water. Engine cooled fine after that and subsequent years I did the same thing immediately after her getting wet after a haul-out.
Just a thought.
By the way, where in Victoria are you - I'm out by the airport with my boat on the hard in the back yard.
John
Penta is offline   Reply With Quote
Old 04-06-2008, 09:15 PM   #8
Member
 
Join Date: Feb 2008
Posts: 5
RE: Raw Water Cooling

Hey John, that's an interesting idea - Air in the System. I should take the hose off anyway to see if the problem is at the pump or after the exchanger. My boat is moored at Westport same spot since 1974. I, however, just acquired her after 2 years of friendly negotiations with the original owner. This weekend will be it's first real run in over a decade, going around Salt Spring Island, and I'm feeling prepared after doing all the proper fluid and filter changes and system checks. I'll look over the cooling again tomorrow and plan to leave Thursday. Thanks for your interest. I have alot to discuss with my new boat and it's updates.
leojs is offline   Reply With Quote
Old 04-06-2008, 10:05 PM   #9
Senior Member
 
Penta's Avatar
 
City: Sidney, BC
Vessel Name: Penta
Vessel Model: 36' 1961 Sather ex-Gill Netter
Join Date: Dec 2007
Posts: 118
RE: Raw Water Cooling

Joel - great, Westport is where we had Penta for about 10 years until I pulled her and brought her home for a re-fit. Great marina, least it was when we left and now all I have to do is try and get back there next year - good luck I would say!
Cheers
John
Penta is offline   Reply With Quote
Old 04-08-2008, 06:49 AM   #10
Veteran Member
 
Join Date: Dec 2007
Posts: 86
RE: Raw Water Cooling

You might think about having the fuel filtered if the boat's been sitting that long. Could be a lot of junk at the bottom of the tank(s) that will get good and stirred up for the first time in a long time.
AdamT is offline   Reply With Quote
Old 04-08-2008, 08:24 AM   #11
Guru
 
Phil Fill's Avatar
 
City: Everett Wa
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,919
RE: Raw Water Cooling

Having a diver check and clean the out side the through hulls. Most hav a protective screen and it does no take much to restrict the flow.* I have a diver come every 6 moths to check/change the zincs and clean the though hulls, hull and prop of barnacles and growth

*
On the raw water side of the pump from the through hull to the pump the hose must be a non compressing wire enforced hose.* The reason is the pump is sucking which will tend to collapse of regular not wire enforced rubber hose. **On the engine side the hose can be a regular non wire enforced hose because the pump is blowing/pushing the water.

*
Phil Fill is offline   Reply With Quote
Old 04-09-2008, 10:17 AM   #12
TF Site Team/Forum Founder
 
Baker's Avatar
 
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
Posts: 7,332
RE: Raw Water Cooling

Check to see if your water heater is heated by the fresh water loop or the raw water loop. I know most boats nowadays are cooled be the freshwater loop, I did have a boat that was cooled by the raw water side of things and it did cause a problem when things got jammed up in there...I simply bypassed it(temporary fix) and the problem was solved.
Baker is offline   Reply With Quote
Old 04-14-2008, 07:35 PM   #13
Member
 
Join Date: Feb 2008
Posts: 5
RE: Raw Water Cooling

Thanks everyone for your comments, I found the problem. Half way up the intake tube was partially blocked and one of the hoses was falling in on itself. All fixed and my trip around the Island was success and I ran her WOT for a good hour too with perfect temperature. The only problem I can see now is the cost of fuel.
leojs is offline   Reply With Quote
Old 04-15-2008, 02:13 AM   #14
Guru
 
Keith's Avatar
 
Vessel Name: Anastasia III
Vessel Model: Krogen 42
Join Date: Oct 2007
Posts: 2,716
RE: Raw Water Cooling

Cost of fuel? Get an unlimited Boat/US towing policy and have them tow you around for free!
Keith is offline   Reply With Quote
Old 04-21-2008, 06:11 PM   #15
Guru
 
Phil Fill's Avatar
 
City: Everett Wa
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,919
RE: Raw Water Cooling

Joel, I hope you replaced the hose with a wire einforsed hose.* Otherwise it will collapse again.

On the raw water side of the pump from the through hull to the pump the hose must be a non compressing wire enforced hose.* The reason is the pump is sucking which will tend to collapse of regular not wire enforced rubber hose. **On the engine side the hose can be a regular non wire enforced hose because the pump is blowing/pushing the water.

regards

Phil/Fill
Phil Fill is offline   Reply With Quote
Old 06-28-2008, 08:10 AM   #16
Guru
 
Shoalwaters's Avatar
 
City: Rodney Bay Lagoon
Vessel Name: "Dragon Lady"
Vessel Model: DeFever 41
Join Date: Feb 2008
Posts: 681
RE: Raw Water Cooling

I know the problem has been long fixed, but the next time someone does a search for overheating problems, here's a couple more areas to check:

1. If a pump impeller failed in the past, did you find all the pieces? Prime areas to check are inlet side of fuel coolers and other heat exchangers. Look into the heat exchanger tubes; pieces of vane seem to be just the right size to get in there.

2. There is probably a grid on the outside of the hull protecting the raw water intake from ingesting twigs etc. The holes in this grid get progressively smaller with each layer of antifouling applied. The result is overtemp at WOT when the holes get small enough.

Mike
Shoalwaters is offline   Reply With Quote
Old 06-28-2008, 09:49 AM   #17
Senior Member
 
greatpapabear's Avatar
 
City: Guernsey, Channel islands
Vessel Name: Play d'eau
Vessel Model: Fleming 55
Join Date: Jun 2008
Posts: 356
RE: Raw Water Cooling

In cases such as you describe, I have found two culprits.

Hoses suffering from internal delamination an/or calcium build up. My recommendation is that hoses should be changed every 5 years.

Rubbish build up in the hosing between the impeller and the exchanger or intercooler. This happens when an impeller has broken up and the bits have travelled downstream.

Hope this helps.
greatpapabear is offline   Reply With Quote
Old 06-29-2008, 03:21 AM   #18
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 22,553
RE: Raw Water Cooling

" If a pump impeller failed in the past, did you find all the pieces?"

For a cruiser this is an ongoing hassle as pump failure is almost inevitable.
Esp in brown water with sand and silt .

Our solution for the offshore boats we built was a large Sen Dure "Y" strainer AFTER the impeller water pump.

IF there are loose pieces (even heavy dust) , there all caught in an EZ to clean strainer.

Today the Dry Stack & keel cooling is a better choice for a newbuild.

Far less danger and maint.
FF is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Oil cooler on FW instead of raw water side of the cooling system Chris Foster Power Systems 73 03-19-2016 10:27 PM
Head Flush - Raw water vs Fresh water HeyJude Other Trawler Systems 50 05-16-2012 12:25 PM
Cooling water intake markpierce Power Systems 14 11-12-2011 07:58 AM
Raw Water Pump Impeller dvd Power Systems 6 06-09-2011 03:23 AM
A/C cooling water flow alarm Keith Other Trawler Systems 8 09-16-2009 07:45 PM

» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 06:41 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012