Thermostat/temp

Joined
Sep 27, 2024
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Hi all,

I just replaced my thermostat (Merc, 160F) and gaskets on my 5.0 MPI and then ran it on muffs to test my water distribution housing after fixing it with JB marine weld (success!).

After getting up to temp, my gauge levels out just above the 175 mark. Assuming it isn't supposed to go above 160, is this an issue? If so, something tells me it could be a faulty sensor or gauge considering my last tstat last year did the exact same thing. Should I be concerned?

I've uploaded some images of the gauge with the boat off then at temp:


Any insight is greatly appreciated!

Thank you.
 

alldodge

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Verify with a IR temp gun on the thermostat housing but I've read many post here and FB about the quad gauges on a Chap

Hope your trim gauge is not accurate because should not run a motor with the trim that high
 

badrano

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Aug 7, 2018
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Temp gauge reading is the same for my 6.2 MPI with 160 thermostat whether on muffs or in the water. I know the voltage gauge is a little off on my boat....yours looks like what I would expect.
 
Joined
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Verify with a IR temp gun on the thermostat housing but I've read many post here and FB about the quad gauges on a Chap

Hope your trim gauge is not accurate because should not run a motor with the trim that high
So an IR temp gun on thermostat housing should read 160?

Yikes, it was up all the way as it's trailered but I guess I should drop it down when starting it on muffs 🤦🏼‍♂️ I never thought about that. Is it because it could cut off water supply?

Thank you for the heads up.
 

alldodge

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So an IR temp gun on thermostat housing should read 160?
It should read close to that
Yikes, it was up all the way as it's trailered but I guess I should drop it down when starting it on muffs 🤦🏼‍♂️ I never thought about that. Is it because it could cut off water supply?
It's real hard on the bellows and the U joints

Should be no higher than the trim limit
 
Joined
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It should read close to that

It's real hard on the bellows and the U joints

Should be no higher than the trim limit
Got it, I'll check with the thermometer.

And that makes sense .. I feel like an idiot, but at least I did just rebuild and service the entire outdrive. I will make sure I don't do that again! 🤦🏼‍♂️

Is it OK to store it with it trailered up all the way? As I don't imagine the strain on the bellows or U joints would be much different when it's running on muffs in idle vs just sitting there with the motor off, would it? Or strictly just when transporting it and then drop it down a bit again (and not forget to bring it back up 😅)
 
Last edited:

alldodge

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Got it, I'll check with the thermometer.

And that makes sense .. I feel like an idiot, but at least I did just rebuild and service the entire outdrive. I will make sure I don't do that again! 🤦🏼‍♂️

Is it OK to store it with it trailered up all the way? As I don't imagine the strain on the bellows or U joints would be much different when it's running on muffs in idle vs just sitting there with the motor off, would it? Or strictly just when transporting it and then drop it down a bit again (and not forget to bring it back up 😅)
You can store with it full up, but many including my self do not.

Storing it full up keeps the bellows stretched out. Over time it will cause cracks sooner. I lower mine down as far as possible to make it last longer. I pull drive every year and check everything. Replaced my bellows for first time at 21 years and it didn't need it then.

https://forums.iboats.com/threads/bravo-itis-fix.680176/
 

Scott06

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Apr 20, 2014
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So an IR temp gun on thermostat housing should read 160?

Yikes, it was up all the way as it's trailered but I guess I should drop it down when starting it on muffs 🤦🏼‍♂️ I never thought about that. Is it because it could cut off water supply?

Thank you for the heads up.
No with a 160 stat the engines run about 170-175 so what you see is completely normal . My 5.0 with same stat runs the same temp.
 

alldodge

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My Rinker 454 and Formula with 509, 530 HP both had 160 Stats, and both never got above 160 unless unless I'm running WOT for a long period
 
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