why don't OBs have a water temp sensor besides squeal

wn6ngp

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Aug 12, 2012
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Why is it that with OB's they don't use a water temperature gauge? I know that water pump pressure is very important and is measured but it seems like it would be just as important to see the actual engine temperature in case the system picked up some blockage. I think most have a squeal sensor but it is kinda like the idiot lights of old, when you hear that it might be too late to save it. Not to mention on my 90elpt I don't hear it during start up to validate its working.
 

jbcurt00

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Please dont start multiple topics about the same subject, duplicate deleted

Never owned a modern enough outboard to have either warning method....
 

racerone

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???----No big deal here.----Hurry and run to a boat shop and have an accessory temperature gauge installed !
 

wn6ngp

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Aug 12, 2012
Messages
209
Why is it that with OB's they don't use a water temperature gauge? I know that water pump pressure is very important and is measured but it seems like it would be just as important to see the actual engine temperature in case the system picked up some blockage. I think most have a squeal sensor but it is kinda like the idiot lights of old, when you hear that it might be too late to save it. Not to mention on my 90elpt I don't hear it during start up to validate its working.
 

dingbat

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High coolant temps are the result of poor or lack of water flow

I would rather monitor the cause than the result
 

JimS123

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I've seen water temp gauges as std equipment on some OB boats. Newer Mercs with an ECM have a lot of readable data if you add a VesselView App on your smartphone.

I always thought the App was a waste of money and then I finally broke down and bought 2 of them. Funny thing - the very first time out I picked up a plastic bag on my lower unit while at cruising speed. Had the phone on the dash on a mount and just by luck I glanced at the screen and saw the temp rising. I stopped and investigated and saw the bag fall off. Then the temp went right back down. Now to me its a bargain priced option.
 

Chris1956

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Mar 25, 2004
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Most of the older inline Mercury motors didn't have a thermostat. They ran dead cold at idle and warmer at cruise. A temperature gauge would therefore show nothing most of the time, until the motor overheated.

Johnnyrudes always had thermostats, and therefore could have gauge senders. However, a water pressure gauge is much better than a temp gauge, for the reasons listed, and not many folks wanted both gauges.
 

wn6ngp

Petty Officer 1st Class
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Aug 12, 2012
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209
why don't OB's have water temp sensor?

I have a gauge for water pressure however I'd like to have one for water temperature. Is there a reason that this is not commonly done except for a warning buzzer?
 

QBhoy

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Mar 10, 2016
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Telltale is always worth looking at. But can tell you that most modern outboards can display water temp and pressure on the dash.
 

bruceb58

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Mar 5, 2006
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Actually, a temp gauge would be nice to also see if the engine is getting up to temp. My 90HP Mercury had a cup of water in the crankcase at the end of a season because the thermostat stuck open. When I put my Rinda on the motor at the end of the season it indicated a low temp error which made me then look at the thermostat.
 
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