Running Hot??

Run n hot

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Joined
Aug 25, 2024
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I have a 2012 mercury 60Hp Bigfoot 4 stroke. It has about 223 hours on it. It was running perfect as always. Then one afternoon it went into guardian mode ( limp mode ). It would only rev to 3000 RPMs before going into guardian mode. it will run all day at 2800RPM without going into guardian mode. The computer was showing over heating and the oil pressure fine. I had the system flushed and replace the impeller first, didn't work. Replaced the temp censor , didn't work. I personally replaced all the fuel filters change the oil, lower unit gear oil, nothing worked. I had other mechanics replace solenoids , among other parts chasing this problem. Has anyone had this problem?
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,068
I have a 2012 mercury 60Hp Bigfoot 4 stroke. It has about 223 hours on it. It was running perfect as always. Then one afternoon it went into guardian mode ( limp mode ). It would only rev to 3000 RPMs before going into guardian mode. it will run all day at 2800RPM without going into guardian mode. The computer was showing over heating and the oil pressure fine. I had the system flushed and replace the impeller first, didn't work. Replaced the temp censor , didn't work. I personally replaced all the fuel filters change the oil, lower unit gear oil, nothing worked. I had other mechanics replace solenoids , among other parts chasing this problem. Has anyone had this problem?
Did you clear the codes after doing the work?
 

Run n hot

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Aug 25, 2024
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5
I'm still looking for some help with this one. Anyone out there had this happen?
 

Chris1956

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Mar 25, 2004
Messages
27,840
The thermostats are generally 140*F. The engine will generally run a bit hotter than that, say 175-190*F.
 

Run n hot

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Joined
Aug 25, 2024
Messages
5
We had the laptop hooked up to the motor as we were on the water running diagnostic. It said it was getting hot. Even changed the temp sensor.
 

Faztbullet

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Joined
Mar 2, 2008
Messages
15,902
1) Does it have a extension?
2) T-stat checked for sticking open? (120°)
3) Cylinder leakdown?
 
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