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07-01-2017, 09:51 AM
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#1
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Senior Member
City: Chesapeake, VA
Vessel Name: Grace
Vessel Model: 1982 Grand Banks Motoryacht
Join Date: Apr 2013
Posts: 134
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Lehman 120 temp GB 42 single diesel
Running across the albemarle sound today, quite bouncy. Temp going up above 200 @1800 rpm. Throttle back to 1500 and back down 180-190.
Both lower and upper helm agree.
What temperature should my Lehman 120 Run? Gonna troubleshoot tonight.
Kurt
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07-01-2017, 10:15 AM
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#2
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Senior Member
City: LAFAYETTE,LA
Vessel Name: Relenti
Vessel Model: Atlantic 30, 1983
Join Date: Mar 2015
Posts: 451
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Sounds like its time to inspect all your engines coolant components-raw water impeller, coolant level, oil level, heat exchanger, etc. Don't forget the thermostat. Also, might want to get a reading on engine with a heat gun.
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07-01-2017, 10:21 AM
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#3
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,151
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3 simple things, depending on how bouncy at 1800 rpms, could have been sucking air into an intake, not likely but possible in teally rough conditions.
Second, could have sucked something up and it blocked some water flow.
3rd, could have pucked up a crab pot and the higher RPMs is making the engine work harder than the cooling system can cool....notice any black smoke?
Along with those possibles, then a methodic check of water flow is a good idea.
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07-01-2017, 10:46 AM
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#4
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Senior Member
City: Anchor Pointe, Ohio
Vessel Name: Sea Moose
Vessel Model: 1976 34' D/C Taiwanese Trawler
Join Date: Oct 2007
Posts: 360
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Get a cheap IR heat gun. My temp gauges are way off. Bob Smith told me before he passed that the high temp alarm is the most accurate.
With the IR heat gun take several readings, as the angle humidity, and material can affect it.
HTH
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07-01-2017, 02:45 PM
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#5
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Guru
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
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Temp that increases with load usually indicates restricted raw water flow.
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07-02-2017, 08:13 PM
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#6
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Senior Member
City: Chesapeake, VA
Vessel Name: Grace
Vessel Model: 1982 Grand Banks Motoryacht
Join Date: Apr 2013
Posts: 134
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I took IR readings all over the engine and could not find over 140 degrees.
I had 140 at the water tank on the front of the engine.
I had like 113 on the valve cover.
I am underway tomorrow and will map out the temps so I can evaluate. For what it's worth, bother lower helm and upper helm agreed.
Regards,
Kurt
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07-03-2017, 12:07 AM
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#7
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Guru
City: Sydney
Vessel Name: Sojourn
Vessel Model: Integrity 386
Join Date: Oct 2011
Posts: 13,333
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Try testing at the sender location. That will tell you if the temp displayed is correct. Something has changed, what it it, and why.
__________________
BruceK
2005 Integrity 386 "Sojourn"
Sydney Australia
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07-03-2017, 07:20 AM
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#8
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Guru
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48 (sold)
Join Date: Apr 2008
Posts: 10,186
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As you check temps with IR gun keep in mind it is coolant temperature that is critical for gauge comparison purposes. Raw water, valve cover or other points have their own curiosities and ranges.
BTW, to insure your IR gun is not deceiving you check against a spoon immersed in boiling water. Last but not least, check your gauge wiring and spray retightened ends with an electrical lube.
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07-03-2017, 08:24 AM
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#9
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Senior Member
City: Chesapeake, VA
Vessel Name: Grace
Vessel Model: 1982 Grand Banks Motoryacht
Join Date: Apr 2013
Posts: 134
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I cleaned the raw water strainer while we were in Port. We are underway today and reading 180 at 1900 rpm. I checked block near temp sensor in two places and got a steady 170. The strainer did not look that clogged, but it appears to be better now. I got 8 hours of steaming today, we shall see. Thanks for all the replies.
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07-03-2017, 04:18 PM
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#10
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Dauntless Award
City: Wrangell, Alaska
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,820
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Quote:
Originally Posted by kurt.reynolds
I took IR readings all over the engine and could not find over 140 degrees.
I had 140 at the water tank on the front of the engine.
I had like 113 on the valve cover.
I am underway tomorrow and will map out the temps so I can evaluate. For what it's worth, bother lower helm and upper helm agreed.
Regards,
Kurt
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First. Pick a spot on your engine coolant tank and use that spot as your reference.
IR gun should be inches away for most accurate results.
How far above 200°?
220° or 280° sorta makes a difference.
If i raise rpms from 1500 too 2000, I expect the temp to go up (It goes to 200 to 210°) since at 15 to 1600 rpms I think the thermostat is the only thing keeping the temperature up. U
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07-06-2017, 06:23 PM
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#11
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Senior Member
City: Chesapeake, VA
Vessel Name: Grace
Vessel Model: 1982 Grand Banks Motoryacht
Join Date: Apr 2013
Posts: 134
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So I have figured out it is the temperature gage on the flying bridge that is in error. I have done an IR Temp on the engine and verified the lower helm temp gage is right.
The Temp gage on the upper helm fluctates with RPM, turn on the instrument lighting and it jumps 20 degrees and reads consistently 15 degrees high at 1900 rpm steady cruising.
Now I need to decide what do do about my temperature instrumentation.
I am guessing there are a lot of options, will be investigating.
Thanks for all the thoughtful and insightful replies. You guys are the best.
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07-06-2017, 06:58 PM
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#12
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Enigma
City: Slicker?
Join Date: Oct 2007
Posts: 16,566
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Greetings,
Mr. k. Sounds to me more like an electrical problem that is outside the gauge (ground, bad connection, high resistance connection...) rather than the internals of the gauge itself but that's just a guess. Any gauges I've ever had fail were either go or no go.
__________________
RTF
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07-06-2017, 07:14 PM
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#13
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Guru
City: Port Townsend
Vessel Name: The Promise
Vessel Model: Roughwater 35
Join Date: Sep 2012
Posts: 1,569
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Mr. K, Mr. RT usually make a pretty good guess. I guess.
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07-06-2017, 07:54 PM
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#14
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Senior Member
City: Anchor Pointe, Ohio
Vessel Name: Sea Moose
Vessel Model: 1976 34' D/C Taiwanese Trawler
Join Date: Oct 2007
Posts: 360
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Quote:
Originally Posted by RT Firefly
Greetings,
Mr. k. Sounds to me more like an electrical problem that is outside the gauge (ground, bad connection, high resistance connection...) rather than the internals of the gauge itself but that's just a guess. Any gauges I've ever had fail were either go or no go.
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Second the motion that Mr. RT is correct. Temp gauges measure resistance, which means any resistance in the circuit counts. if the gauges haven't been replaced it's wiring, start with the ground path. If one has been replaced and the other hasn't... that will cause similar problems.
After chasing electrical gremlins for years I just gave up, I know the engine is 20 degrees cooler than the flybridge says, and I know the RPM is off. I'm on Lake Erie so TowBoat is never far away...
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07-07-2017, 01:51 AM
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#15
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Dauntless Award
City: Wrangell, Alaska
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,820
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Quote:
Originally Posted by SeaMoose
Second the motion that Mr. RT is correct. Temp gauges measure resistance, which means any resistance in the circuit counts. if the gauges haven't been replaced it's wiring, start with the ground path. If one has been replaced and the other hasn't... that will cause similar problems.
After chasing electrical gremlins for years I just gave up, I know the engine is 20 degrees cooler than the flybridge says, and I know the RPM is off. I'm on Lake Erie so TowBoat is never far away...
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third the motion
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