Faria Cyl Head Temp Gauge

[Fisher1977]

I bought a Faria cylinder head temp gauge to install on my 86, 175 Mercury Black Max. It came with a sending unit, with a bracket on it. In the directions is says to remove a head bolt to install the sending unit, and reinstall the head bolt, and torque it to specs. I am not sure if I should remove a head bolt or not. Don't seem like the right thing to do. I have been a diesel mechanic for 20 years, and have never just removed 1 head bolt, and put it back in. Has anyone done this? Any other ideas on where to put the sending unit? Thanks for any help.

 

[Faztbullet]

Tweak the bracket and use the 5/1 bolts on water jacket....or better take it back and install a water pressure guage.

 

[Silvertip]

You are working on an outboard motor that has a compression ratio of somewhere around 7:1, not a diesel engine with a 23+ compression ratio. Head bolts on these motors and the torque pattern are important, but you can safely pull one and reinsert it. My preference is to install both a water pressure gauge and a temperature (water or head) gauge. Water pressure gauges tell you there is water pressure. They do not tell you the engine is cooling properly -- although they do have an overtemp sender that may or may not trigger soon enough to save a motor. But then either gauge is of little use either unless one looks at them now and then. I'm betting 80% of the boaters would head back to the dock if either gauge indicated an issue and then complain because the engine died on the way.

 

[Fisher1977]

Thanks for the replies. I appreciate the help Silvertip. You are right on, I am used to the diesels. You just don't mess with the head bolts on them, unless you are pulling the head. I agree that both a temp, and pressure gauges should be installed. Just because there is water pressure doesn't mean that a thermostat isn't stuck closed, or some other problem exists that can cause a engine to overheat. Those gauges have saved me several times over the years in my vehicle, and on my boats. I have shut the outboard down more than once, and used the trolling motor to get back to the dock.

 

[Dukedog]

picture of the sensor?

 

[Fisher1977]

Here is one like I have.

 

[Dukedog]

sorry, not familiar with that one......