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26-07-2015, 12:25
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#1
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Registered User
Join Date: Jul 2015
Posts: 11
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Overheated
Would anyone know besides water flow what would cause over heating of a Yanmar 315? I have cleaned every cooler replaced perfectly good impeller and even replaced the thermostat. At idle and at higher rpms the water is moving, yet as soon as I put it under load to come up on plane the temp still pegs within 30 seconds.
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26-07-2015, 13:02
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#2
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Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
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Re: over heated
Quote:
Originally Posted by dspringer
Would anyone know besides water flow what would cause over heating of a Yanmar 315? I have cleaned every cooler replaced perfectly good impeller and even replaced the thermostat. At idle and at higher rpms the water is moving, yet as soon as I put it under load to come up on plane the temp still pegs within 30 seconds.
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There was another thread with about the same problem and for him it was air in the system. With a Perkins there are 2 pipe plugs on the top of the cylinder head for bleeding the air out. If he had a manual he would have probably known that at the beginning. Any chance you need to bleed the system of air too?
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26-07-2015, 13:08
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#3
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Registered User
Join Date: Jul 2015
Posts: 11
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Re: over heated
That is a possibility, I haven't tried that yet. thanks for the input! if you hear of anything else let me know please.
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26-07-2015, 15:03
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#4
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Senior Cruiser
Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 3,499
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Re: Overheated
I assume you have a good flow thru the salwater side... The freshwater side could need a good flush. Make sure there is good flow thru the heat exchanger on both sides. I have seen overheat problems where the freshwater system was corroded and not found until hunting problems after going thru the saltwater side.
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26-07-2015, 15:06
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#5
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Registered User
Join Date: Sep 2006
Posts: 9,398
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Re: Overheated
It's not a faulty temperature gauge?
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26-07-2015, 15:20
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#6
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Registered User
Join Date: May 2006
Location: Queensland, Australia
Boat: Maxim 38 ft catamaran
Posts: 284
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Re: Overheated
Check rubber hoses ,can look good at idle but once under pressure suction can make old worn hoses" close in "and restrict water supply,particularly on bends.
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26-07-2015, 15:25
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#7
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Registered User
Join Date: Nov 2014
Posts: 1,778
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Re: Overheated
Sounds a lot like you have a lose belt.
Sent from my XP7700 using Cruisers Sailing Forum mobile app
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26-07-2015, 16:02
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#8
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Registered User
Join Date: Jul 2015
Posts: 11
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Re: Overheated
Quote:
Originally Posted by Lepke
I assume you have a good flow thru the salwater side... The freshwater side could need a good flush. Make sure there is good flow thru the heat exchanger on both sides. I have seen overheat problems where the freshwater system was corroded and not found until hunting problems after going thru the saltwater side.
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I had the exchangers removed and cleaned and the coolant flow is good. The salt water flow is also good. We checked all the hoses for collapsing at high Rpm too and all seem to be good to go.i had the engine gunned at over heat and was verified hot. If you any other ideas I would love to hear. anything thanks so much
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26-07-2015, 16:03
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#9
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Registered User
Join Date: Jul 2015
Posts: 11
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Re: Overheated
Quote:
Originally Posted by FamilyVan
Sounds a lot like you have a lose belt.
Sent from my XP7700 using Cruisers Sailing Forum mobile app
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I thought maybe too and did a belt tighten with no change. Thank you so much. Anything else comes to mind let me know.
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26-07-2015, 16:14
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#10
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Registered User
Join Date: Nov 2014
Posts: 1,778
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Re: Overheated
I had this exact problem about 3 months ago. I had two problems. Belt (as I mentioned) and travellers. I'd been a ground and picked up a bunch of weeds on my skeg. Might be worth checking your keel, prop, shaft and rudder for debris like weeds, line or nets.
Sent from my XP7700 using Cruisers Sailing Forum mobile app
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26-07-2015, 16:37
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#11
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Registered User
Join Date: Apr 2011
Location: Naples, FL
Boat: Beneteau Oceanis 400
Posts: 669
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Re: Overheated
It sounds like you have checked all of the obvious stuff, assuming that you good salt water flow, and good fresh water flow, the next place to look is the engine itself. Could the timeing be off by one belt cog. If your injector timing or cam timing is off slightly this can cause over heating. A sticky valve or a froze valve would cause over heating when under power. A leaking head gasket, or a cracked head would also cause it. I would check the timimg first, then do a compresion test, that will tell you the general health of the enging. How many hours are on the enging? Lot's of stuff to check.
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27-07-2015, 07:33
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#12
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Registered User
Join Date: Jul 2015
Posts: 11
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Re: Overheated
Quote:
Originally Posted by Rocketman
It sounds like you have checked all of the obvious stuff, assuming that you good salt water flow, and good fresh water flow, the next place to look is the engine itself. Could the timeing be off by one belt cog. If your injector timing or cam timing is off slightly this can cause over heating. A sticky valve or a froze valve would cause over heating when under power. A leaking head gasket, or a cracked head would also cause it. I would check the timimg first, then do a compresion test, that will tell you the general health of the enging. How many hours are on the enging? Lot's of stuff to check.
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That's good intel, thank you very much. I haven't checked the timing or done a compression test yet. The engines have about 450 hrs but are 10yrs old. It creeps up slightly at idle just maybe 15 to 20 degrees hotter than usual but gets hot immediately when put under power. Would you think that be consistent with one of these issues?
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27-07-2015, 07:45
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#13
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Moderator Emeritus
Join Date: Sep 2007
Location: Eastern Tennessee
Boat: Research vessel for a university, retired now.
Posts: 10,406
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Re: Overheated
I wonder if there might be corrosion or a coating of some sort inside your block acting as a heat insulator?
__________________
David
Life begins where land ends.
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27-07-2015, 08:31
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#14
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Registered User
Join Date: May 2010
Location: Elsewhere on the Water
Posts: 579
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Re: Overheated
Quote:
Originally Posted by dspringer
I had the exchangers removed and cleaned and the coolant flow is good. The salt water flow is also good. We checked all the hoses for collapsing at high Rpm too and all seem to be good to go.i had the engine gunned at over heat and was verified hot. If you any other ideas I would love to hear. anything thanks so much
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I had this same problem. I also removed the hoses and looked inside, and found them clear of any obstructions. In my case the multi layer, wire reinforced hoses had delaminated. The result was they looked OK, but cutting one in the middle demonstrated that the inner layer was detached from the outer layer. Suction from the pump at high RPM's caused the inner layer to collapse. New hoses solved the problem. I strongly recommend that you cut one open, and replace all hoses on the suction side of the pump if they are delaminated.
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27-07-2015, 08:55
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#15
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Registered User
Join Date: Jul 2015
Posts: 11
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Re: Overheated
Quote:
Originally Posted by St. Elsewhere
I had this same problem. I also removed the hoses and looked inside, and found them clear of any obstructions. In my case the multi layer, wire reinforced hoses had delaminated. The result was they looked OK, but cutting one in the middle demonstrated that the inner layer was detached from the outer layer. Suction from the pump at high RPM's caused the inner layer to collapse. New hoses solved the problem. I strongly recommend that you cut one open, and replace all hoses on the suction side of the pump if they are delaminated.
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Thanks for the response. I have replaced a few hoses but recently did an experiment and at high RPM's and the water flow increased at the exhaust riser perfectly. I would expect it to decrease if the suction collapses one or more of the hoses. I'm still going to take your advise and finish replacing the rest of the hoses. thanks again.
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