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30-06-2014, 08:58
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#16
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S/V rubber ducky
Join Date: Jul 2007
Location: heading "south"
Boat: Hunter 410
Posts: 20,362
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Re: More flow for cooling
Shut the raw water engine supply valve, take the hose off it, open the valve and see what the flow is like.
If there is a good flow then the through valve/inlet isn't the problem. The engine doesn't need a lot of water to keep cool. I normally know that my strainer needs to be cleaned by the exhaust smell from less water flow way before temperature (never have had a temperature problem).
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Don't ask a bunch of unknown forum people if it is OK to do something on YOUR boat. It is your boat, do what you want!
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30-06-2014, 08:59
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#17
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S/V rubber ducky
Join Date: Jul 2007
Location: heading "south"
Boat: Hunter 410
Posts: 20,362
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Re: More flow for cooling
Quote:
Originally Posted by ranger42c
Hmmm... how does the sink water drain overcome seawater pressure?
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because the bottom of the sink is above the waterline
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Don't ask a bunch of unknown forum people if it is OK to do something on YOUR boat. It is your boat, do what you want!
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30-06-2014, 12:06
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#18
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Registered User
Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 13,479
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Re: More flow for cooling
Before you try and plumb around it, I suggest you isolate and resolve the problem. I assume it has not always done this so something has changed.
Start at the intake and work your way all the way thru the system on component at a time.
For example:
Have you cleaned the heat exchanger?
Inspected/cleaned exhaust elbow?
...
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30-06-2014, 12:08
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#19
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Registered User
Join Date: Aug 2012
Location: Maryland, USA
Boat: 58' Sedan Bridge
Posts: 5,418
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Re: More flow for cooling
Quote:
Originally Posted by sailorboy1
because the bottom of the sink is above the waterline
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Ah.
I guess.
So that would sorta mean sink drainage would always be hanging around in the discharge line?
BTW, I should have added a "to my knowledge" to my statement about not ever being on an "our size" boat with underwater sink drains. The powerboats I've been on but am least familiar with would have been Nordhavns and Kadey Krogens, and then I've only been underway on two handfuls of sailboats... so I didn't mean to imply deep knowledge on the topic.
-Chris
__________________
Chesapeake Bay, USA.
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30-06-2014, 13:20
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#20
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: More flow for cooling
Quote:
Originally Posted by ranger42c
Ah.
So that would sorta mean sink drainage would always be hanging around in the discharge line?
-Chris
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Unless your un the habit of flushing it out with plenty of water, yes.
This is another reason not to T anything that pulls water into a sink discharge line
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30-06-2014, 13:37
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#21
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Registered User
Join Date: Apr 2006
Posts: 4,413
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Re: More flow for cooling
I am going to change the exhaust elbo...coming tomorrow.. the present one is 13 yrs old and probably corroded and blocked... it shows some corrosion on the outside and it's time to renew it anyway. Heat exchanger could perhaps use cleaning. I'll do that project with the new elbo.
Low revs it does not go hot... so I think it's a restriction.
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30-06-2014, 13:57
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#22
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S/V rubber ducky
Join Date: Jul 2007
Location: heading "south"
Boat: Hunter 410
Posts: 20,362
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Re: More flow for cooling
Quote:
Originally Posted by Sandero
I am going to change the exhaust elbo...coming tomorrow.. the present one is 13 yrs old and probably corroded and blocked... it shows some corrosion on the outside and it's time to renew it anyway. Heat exchanger could perhaps use cleaning. I'll do that project with the new elbo.
Low revs it does not go hot... so I think it's a restriction.
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you are going to start with hard stuff before you even check the flow though the valve?
__________________
Don't ask a bunch of unknown forum people if it is OK to do something on YOUR boat. It is your boat, do what you want!
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30-06-2014, 14:07
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#23
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Registered User
Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,108
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Re: More flow for cooling
Quote:
Originally Posted by Sandero
Low revs it does not go hot... so I think it's a restriction.
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Low revs produce less heat. It sounds like the symptoms we get when our exhaust elbow is mostly coked up or rusted.
SB is correct , though - you really should check the simple things first.
Mark
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You do not need a parachute to skydive. You only need a parachute to skydive twice.
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30-06-2014, 14:35
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#24
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: More flow for cooling
He's right to change it, 13 yrs? even if it's not what is causing the current temp problem and I bet it isn't, it's sure to fail soon and that can be expensive.
Personally I tend to "shotgun" systems, that is go trough it all, then enjoy a long time of trouble free service, it's either that or be constantly be fixing something.
I'd clean the strainer, and I bet that is the problem, but also the heat exchanger, change the thermostat and flush the fresh water side and of course put in new coolant. Might even be tempted to change out the water pump depending on age and hours.
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30-06-2014, 14:36
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#25
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Registered User
Join Date: Jan 2013
Location: Adelaide Australia
Boat: Cuddles 30ft Motor Sailer
Posts: 286
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Re: More flow for cooling
Quote:
Originally Posted by sailorboy1
Shut the raw water engine supply valve, take the hose off it, open the valve and see what the flow is like.
If there is a good flow then the through valve/inlet isn't the problem. The engine doesn't need a lot of water to keep cool. I normally know that my strainer needs to be cleaned by the exhaust smell from less water flow way before temperature (never have had a temperature problem).
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+1
This is a quick easy check.
Sandero - Is the engine raw water cooled or does it have a heat exchanger? If RWC - the MD17's tend to block up at the point where the raw water enters the engine block.
If FWC, then the blockage may be the exhaust elbow.
The thermostat could also be the problem if it is gummed and and not opening fully.
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30-06-2014, 18:43
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#26
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Moderator Emeritus
Join Date: May 2007
Location: Ohio
Boat: Now boatless :-(
Posts: 11,580
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Re: More flow for cooling
Beat thread EVER!
This is freakin' hilarious.
I think you need to change the galley sink.
Seriously -
With the engine cold
- Remove hose from inlet of water pump - No flow? Clear obstruction. Reattach hose
- Remove the hose that goes from heat exchanger to exhaust elbow
- Start engine - observe flow Good flow? Replace/clean exhaust elbow. No flow?
- Remove hose from inlet of heat exchanger. Good flow? Clean heat exchanger
- Heat exchanger blocked.
Was the impeller "really" in good shape?
Also this can be an expensive lesson if not fixed right. I would also check fresh water coolant level and with engine warm and running observe thorugh the fill cap that water is circulating.
This could also be a thermostat problem.
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01-07-2014, 03:33
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#27
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Registered User
Join Date: Apr 2006
Posts: 4,413
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Re: More flow for cooling
Thanks for all the suggestions.
fresh water cooled
coolant is old and topped up shouldn't have any inpact on flow of RW)
The seacock could be mucked up... Diver cleared the outside thru hull.
The strainer is clean... it a bit of eel grass inside
T stat could be mucked up... would that restrict flow?
new RW impeller did not change the flow rate
heat exchanger could be mucked up (will clean)
elbow is old and shows some external corrosion... suspected as the flow restriction needs to be replaced in any case.
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01-07-2014, 04:03
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#28
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Registered User
Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 13,479
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Re: More flow for cooling
T'stat won't restrict raw water flow (its in fw side), but can effect engine temp.
I would place my bets on heat exchanger and/or exhaust elbow (given the stated age it almost certainly needs to be replaced). Intake plumbing wont fix either of these issues and not resolving them could result in a damaged engine.
If you've replaced impellers, but not cleaned the heat exchange tube in a while you will likely find bits of impeller blades obstructing it.
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01-07-2014, 04:05
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#29
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Registered User
Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 13,479
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Re: More flow for cooling
(duplicate)
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01-07-2014, 04:17
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#30
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Registered User
Join Date: May 2006
Location: Solomons, MD
Boat: Beneteau Oceanis 400
Posts: 244
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Re: More flow for cooling
I'm going to second checking your mixing elbow. I am replacing mine today as I have had the same issue of running hotter. Apparently these get clogged up with carbon and restrict exhaust gases causing a hotter engine.
Sent from my iPad using Cruisers Sailing Forum
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