Head temp gauge, water temperature, water pressure gauge.......1992 2.5L Merc 200 hp

All:

I want to make sure I am properly equipped with information to make sure I don't burn my powerhead up. This is on a 21' open bow runabout boat. I have a few questions:

My boat came with the standard head temperature gauge. 100* - 240*. I believe the sending units are located just under the top spark plugs on each side of the block. Tan lines feeding into the Merc Harness. What should this gauge read at typical 3500-4000 RPM? What reading is the danger zone (and time to shut down)?

I know I need a water pressure gauge. I just ordered one online. Where do I tap into the block? I have read on another post that I tee into the tall tale in the top of the block right behind the flywheel? On my engine, it is a rather large fitting, maybe 3/4" threaded into the block with a 90* fitting on it. Is this the tall tale? Do I simply "T" into this and then run the line up to the dash?

Lastly, it would seem to make sense to me to have some form of a water temp gauge, so I ordered one with the brass sending unit. Where would I tap into the block / water line to get an accurate reading of the water temperature?

Thank you in advance.

HD

Re: Head temp gauge, water temperature, water pressure gauge.......1992 2.5L Merc 200

Anybody? I appreciate any help.

Thanks.

Re: Head temp gauge, water temperature, water pressure gauge.......1992 2.5L Merc 200

I'm not sure about the temp guage but the sensor is already in the head two wires go to the ecu and the other is for a temp guage. For the wp on my 2.5 I have a fiting on top of the exhaust divider plate.