Engine Temp sensor

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britinusa

Our boat is 30 minutes travel from home, so I like to be prepared before heading to the boat to work on a project.

The engine temp gauge is not working, can someone point out where on the engine the temp sensor is located.

Is it a block temp sensor or coolant temp sensor and where is it located.

I was thinking of installing something like this

Thanks.

Paul
Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP

Stu Jackson

#1
Paul,

The tech wiki under engines has a link to a discussion of..oh, here it is:

Thermostat Sender Source http://c34.org/bbs/index.php/topic,7985.0.html

Here's a picture of the engine:  http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-m25xp-specifications.html

and

http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-m25-specifications.html


Pretty much the same by pictures.

tag  engine picture
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Craig Illman

Paul - My gauge was seeming to read low, so I replaced with this on my M3-20:  http://www.amazon.com/gp/product/B001RIAJ46/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

$9 was easier to swallow than the price from a Universal dealer or Catalina Direct. Gauges are only about $25-$35. You probably should check wiring continuity first. Ground the sender wire from the Thermostat housing to the block and see if the gauge goes to max.

Craig

KWKloeber

Quote from: britinusa on June 02, 2015, 01:30:36 PM
Our boat is 30 minutes travel from home, so I like to be prepared before heading to the boat to work on a project.

The engine temp gauge is not working, can someone point out where on the engine the temp sensor is located.

Is it a block temp sensor or coolant temp sensor and where is it located.

I was thinking of installing something like this

Thanks.

Paul

What does not working entail?  Dead?  gauge pinned low?  gauge pinned high?
If you search on "gauge troubleshooting" on the TechWiki, there's a guide I had posted.

See the below for the location of the temp gauge sender - on the front of the thermostat cap, 1/4" NPT thread port.

Do you still have the gummy bear plug at either end of the engine-to-cockpit panel harness?

[attachimg=#]

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

britinusa

Thanks guys,

The Gauge seems to be reading a max of 2 indents from the lower limit (not sure what temp that is without going down to the boat to look closely)

Other than not being able to find where the wires run, I should not have a problem testing the wiring.

I'm going to follow the links suggested to see where they go.

Paul
Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP

britinusa

Here's a pic of the Temp Sensors (at least I presume that's what they are!)



Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP

Craig Illman

My guess is that the one pointing forward is the original sender for the gauge and the one pointing starboard is an added high temp alarm sensor.

Craig

britinusa

Thanks,
I hope to get the chance to test them today, will just short them to earth and should get full deflection at the gauges.

If not, then I'll take the control panel off and short them C to earth there that should tell me if I need to replace the Gauge, Wire or Sensors.

Paul
Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP

KWKloeber

#8
Quote from: britinusa on June 13, 2015, 05:04:22 AM
Thanks,
I hope to get the chance to test them today, will just short them to earth and should get full deflection at the gauges.

If not, then I'll take the control panel off and short them C to earth there that should tell me if I need to replace the Gauge, Wire or Sensors.

Paul

Again, the one with the slide on "Packard 56" terminal is not a temp sender -- and has nothing to do with the gauge.  It's a switch that closes around 200F, completes a circuit, and sounds the alarm.  The sender with the post terminal is the gauge sender.  Check it per the troubleshooting guide I posted for resistance before you pull the panel.

kk
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

KWKloeber

Quote from: britinusa on June 02, 2015, 01:30:36 PM

I was thinking of installing something like this

Thanks.

Paul

That link is an alarm, and you already have an alarm (driven by the temp switch on the thermostat cap.)  If the alarm isn't working as well, you can replace it with a Cole-Hersee dual alarm/light that mounts thru the panel, or simply a piezo alarm from Radio Shack. My guess is that the alarm is working.

kk
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

KWKloeber

Quote from: britinusa on June 02, 2015, 04:14:53 PM
Thanks guys,

The Gauge seems to be reading a max of 2 indents from the lower limit (not sure what temp that is without going down to the boat to look closely)

Other than not being able to find where the wires run, I should not have a problem testing the wiring.

I'm going to follow the links suggested to see where they go.

Paul

So, it's reading LOW. 
Again, do you still have the gummy bear plugs in place at the engine and/or cockpit ends of the wiring harness?

See reasons for inaccurate gauge readings, and how to verify:
http://c34.org/bbs/index.php/topic,8493.msg59876.html#msg59876


kk
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

KWKloeber

Quote from: KWKloeber on June 13, 2015, 05:55:07 AM
Quote from: britinusa on June 02, 2015, 01:30:36 PM

I was thinking of installing something like this

Thanks.

Paul

That link is an alarm, and you already have an alarm (driven by the temp switch on the thermostat cap.)  If the alarm isn't working as well, you can replace it with a Cole-Hersee dual alarm/light that mounts thru the panel, or simply a piezo alarm from Radio Shack. My guess is that the alarm is working.

kk

BTW, that's a Japanese engine! Good luck screwing an american' NPT-thread sensor into JIS / BSP threads!   :wink:  That's why some engines had bolt on sensors on the exhaust manifold.

kk
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Ron Hill

Paul : The temp sensor is the one pointed forward in Paul's picture.  The wire should be brown with a ring connector.
Also make sure that you put a protective boot on that connection.  If the metallic insulation on the steps touches that connection you'll get an erroneous reading!!

A thought
Ron, Apache #788

britinusa

A picture gets great responses.

Thanks guys.

I'll check the wiring and get a boot on that sensor.

Ran out of time and energy today. Got a lot done, but exhausted. Working to get the boat ready for the renaming ceremony next weekend.

Paul
Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP