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Temp gauge vs IR reading

B

bobct

Advanced Contributor
http://youtu.be/BmY3VbLIX5k

Another crude video for your viewing pleasure. I replaced the ring terminal on the temp sensor end yesterday but no change. Do the actual temps on the gun look ok compared to the gauge? At WOT it climbs to "190" which is maybe more like 170-175??

Both gauges and sending units are new about three years ago. Ignore the second half, my timing light wasn't firing so I posted the other link.

thanks
Bob
 
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Anything highly reflective (like your brass target) can throw the gun off (very low emissivity targets do not read well). I get good agreement shooting the cast iron right next to the temp sender. I also checked my gun reading on objects in boiling water to make sure it is accurate.
 
Ok, trying to figure out if I have a real issue or not. Here's what I'm getting underway, at cruise after about 45 mins.
I took my readings right at the base of the temp sending unit on the intake manifold:

Port - 133 degrees, gauge reads 185
Starboard - 162 gauge reads around 170

The inboard elbow on the port side did read 20 degrees cooler. I had a similar issue a few years ago when I thought one engine was running "hot"... like I do now. Diver Dave said hold on, your issue is really the other engine is running too cold. Sure enough, I removed the thermostat and it was mangled (by me) and I replaced it and all was well. I need to check my log and see which engine I did the reinstall.

It would seem to me my Stb readings are good all around but my port engine is running to cold AND the gauge is way off regardless. Both engines running fine, very light steam output on both engines of equal amount. That on run this weekend in 75 degree water with 95 degree air temps.

What do you guys think?

Bob
 
Port is running too cold...like Jeff, I'd put more weight on the IR gun.

You can check the gauge with a resistor, 110 ohms. remove the sender wire and hook the resistor between ground and the sender terminal. key on should put the needle at the 50% point (straight up with a conventional gauge). the sender unit can be checked with an ohm meter (varies with temp)...
 
thanks for confirming that Mark. I'm going to swap out the port thermostat like I did on the Starboard side. I wonder if I did the same thing as I did on Stb? I can only guess that I over torqued it or it shifted somehow. Original Stb thermostat (installed by me) look like it was hit with a sledge hammer. Maybe I did this 2x?
 
Also, don't use any Teflon tape or sealer on the sensor threads--just tighten it up dry. The block is part of the circuit (ground return).

Jeff
 
smashing it will likely cause it to run open...that said, for the life of me, I can't fathom how you crushed it if it went into the housing right side up...
 
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