water temp gauge

[lztat573]

I don't think my water temp gauge is working properly. is there a way to test it and or fix it. I used a laser surface temp gun and my boat read around 8 degrees warmer. boat is a 2007 SV211.

[Jonny Quest]

Remove the wire at the sending unit. Ground the wire. If the gauge “pegs” then likely the gauge is OK. Un-ground the wire and watch the gauge. Grounding and ungrounding should peg the gauge and then return back to zero. If the gauge appears OK, likely your sending unit is bad. I’ve had 3 sending units fail in 10 years in the same engine.

JQ

[lztat573]

Thanks for the reply JQ, just need to clarify some things. I'm referring to the digital lake water temp, not the temp of the water in the motor. If we are on the same page. Where is that sending unit?

[Jonny Quest]

Thanks for the clarification...I was referring to the engine water temp gauge. I have no suggestions for the ambient water temp system, sorry.

[Fast351]

I don't think my water temp gauge is working properly. is there a way to test it and or fix it. I used a laser surface temp gun and my boat read around 8 degrees warmer. boat is a 2007 SV211.

My 2007 211 did the same thing. Just live with it, no real way to fix it.

ETA: It did this since new. Not something that changed suddenly or over time.

[homer12]

You could replace that lake sensor but they’re kind of spendy I believe. Mine (2004) doesn’t read correctly either.
Btw, if you reading surface temp of your lake, it could very easily be several degrees warmer than below the surface due to warmer air, sun, etc on surface


Sent from my iPhone using PLT Nautique

[lztat573]

Homer 12. Not sure if the Lazer pointer thermometer is the best thing to try and find water temp, but when I tried it at home in the sink it seamed to work. But when doing it at the lake, I'm not sure if it is getting the surface temp or below, but it read colder then the one on the boat. I'm not sure where the sensor is located, but I'm assuming on the bottom of the boat. So that would be below. I know it's not a big issue but would just like it to read correct temp. Then I know how big of a wuss I am. LOL when i was younger I would get in it when it was really cold to ski, with a wet suit of course, but never did a dry, and now I have a hard time when it isn't at least 70 or above. According to my temp back in the day, I remember the coldest was 49. Skied from early April to end of November in Southern Idaho.

[Fast351]

It is probably a thermistor that is part of the paddle wheel for the Perfect Pass.

No real way to calibrate them. New sensor would probably do the same. I always just assumed when the water started getting colder that the boat was reading 7 degrees high.

We ski from ice off to ice on, depending on outside temp. Usually use the 100 rule (water+air>100) but have broken it occasionally. I skied last year at 35 water 49 air. It was brisk.

My cutoff is below 65 for wetsuit and below 45 for drysuit.