Pressure gauge

[105mich]

Would anyone know how to install a water pressure gauge on a mercury xr4 150 that does not currently have one? It runs at hot at around 200 degrees sometimes and I would like to check water pressures to see if they look good maybe my sensors or temp gauge is bad or off.

 

[Chris1956]

Depending on the year of the motor, some of them have pipe plugs into the water jacket. If you have that, remove one and install a brass fitting to adapt the hose barb that came with the water pressure gauge. Sometimes you need nothing, sometimes a male-male reducer, sometimes just a male to male.

Other motors do not have a pipe plug, so you need to "tee" into a cooling water hose. So you get a brass tee and two male hose barbs to match the water hose, and if needed a fitting to adapt the pressure gauge hose barb to fit the third leg of the Tee.

Clamp all hoses with stainless steel hose clamps

 

[Dukedog]

do as Chris laid out.. there is (depending on yr.) a hose starting on top of block behind flywheel going down to poppet cover on starboard side. tha "t" chris mentioned goes in that hose, on top of tha block.. if yours is tha earlier XR4 without that hose then you will see a pipe plug (as chris says) in tha top of tha block behind tha flywheel.. remove that plug and adapt opening down to size for you gauge fitting.. "ace hardware" is your friend for all things fittings...

 

[Texasmark]

I just bought a 2+2 115. Rather than a pressure gauge, I bought an electric temp gauge. At the top of the water jacket is a ⅛" NPT plug and has about 1 ¾" of space if you stick a pencil in it to see how far it will go ,which is more than enough depth to accept a sensor. Went to ebay and picked up this baby (https://www.ebay.com/itm/Auto-Meter...m=273756602539&_trksid=p2054502.c100227.m3827).

If you get lost in all that "address mumbojumble" just go to ebay and ask for: Auto Meter Old Tyme White Water Temperature 250 Deg F Gauge 2-1/16'' Electrical. Just so happens my instrument panel on my 2002 Crestline 17.5 Fish Hawk has a cutout where it will fit perfectly and the white background matches.

On the water pressure gauge thing, what does it really tell you, or what does the Pee tell you? My pee is plumbed directly off the exhaust manifold plate and is a separate water system so all it tells me is how good is my water pump pumping at a given rpm. What I'm interested in is "what is the engine block internal temp".....aka are my stat and pressure relief working properly......temp monitoring gives you the answer you want.

 

[Dukedog]

does that 'lectric thing even give ya clue as to "why" or "where" as in bad gasket somewhere, worn out pump, poppet blocked/bad etc.... a temp gauge has its place IF you know jus how accurate it is, but diagnostics ain't one of 'em... jmo.

 

[dingbat]

On the water pressure gauge thing, what does it really tell you, or what does the Pee tell you? My pee is plumbed directly off the exhaust manifold plate and is a separate water system so all it tells me is how good is my water pump pumping at a given rpm. What I'm interested in is "what is the engine block internal temp".....aka are my stat and pressure relief working properly......temp monitoring gives you the answer you want.

What does the pressure gauge tell me....

1. Confirms water flow and pressure. Telltale quantifies neither into useful data. Besides, I can’t see my telltale from the helm

2. Provides feedback on condition of water pump. Let’s me know when it’s time to change water pump.

3. Immediate confirmation of thermostat operation. Can watch pressure peaks and valleys when open and close.

3. Immediate indication of the interruption of flow in the cooling system.

Under what conditions would an outboard over heat with ample water flow and functioning thermostats?

Temp is nothing more than confirmation of a reaction to a failed cooling process. As an automation guy, I want to monitor the process, not the reaction to a failed process.

 

[Texasmark]

does that 'lectric thing even give ya clue as to "why" or "where" as in bad gasket somewhere, worn out pump, poppet blocked/bad etc.... a temp gauge has its place IF you know jus how accurate it is, but diagnostics ain't one of 'em... jmo.

No but since I'm deaf and it will mount directly in front of me in a 3 meter display...RPM-Temp-Velocity I can immediately recognize that I have a problem and can shut the engine down before it croaks.....and I don't have to wait to 192 or 195F....forget which, to find out I have a problem.....and the boat has a teeny weeny little LED sized visual indicator that you would have to be looking off to the side to see it......if you could in bright sun light.

 

[Texasmark]

What does the pressure gauge tell me....

1. Confirms water flow and pressure. Telltale quantifies neither into useful data. Besides, I can’t see my telltale from the helm

2. Provides feedback on condition of water pump. Let’s me know when it’s time to change water pump.

3. Immediate confirmation of thermostat operation. Can watch pressure peaks and valleys when open and close.

3. Immediate indication of the interruption of flow in the cooling system.

Under what conditions would an outboard over heat with ample water flow and functioning thermostats?

Temp is nothing more than confirmation of a reaction to a failed cooling process. As an automation guy, I want to monitor the process, not the reaction to a failed process.

Well sir, I want to be alerted that an event is occurring. Will figure out what as an agenda item later......not expecting any problems and on replacing stats for the sake of it, the only stat problem I ever had was on a 1971 Chevy and I had just installed a new stat....forget why....and it fell apart on the way home, towing my boat....of all times to have a problem. So I'm perfectly happy to run the old stat, popoff, and impeller till I get an event......I don't boat offshore....1000 to 30,000 acre lakes.