5.0 MPI Mercruiser Thermostat off 20 Degrees

[easyloader]

My 5.0 mpi mercruiser gauge reading 170, manifolds 80-85 degrees, and sending unit reading 152 degrees.
Do sure how to troubles if issue is gauge, sending unit or something else.
I just replace the 160 degree thermostat.
Any assistance is appreciated.
Thanks

 

[Bt Doctur]

Try replacing the sending unit first , then if your using a laser to verify temps you can use resistors to change the reading of the gauge

 

[QBhoy]

Hi

i have the same engine. The faria gauge reads 160-165 but the smart craft vessel view mobile with its exact data, shows 151-153 constant

 

[easyloader]

Update, I ran the boat to operating temperature roughly 155 degrees at t-stat housing and gauge reading 172. Checked
resistance vs temp chart and resistance is a little off. Bottom line I'll change out sending unit since it's short money and if still off not a huge deal. Not going to spend money n new gauge.