Water pressure gague

Bill Adkins

Seaman
Joined
Sep 27, 2006
Messages
68
I had such a quick and helpful response I thought I try again. I want to install a water pressure gague on a 1970 Merc 1350. I understand the reason or purpose for it but I need to know where it should be hooked up for the most accurate reading to be made. Again thanks in advance for any help. Its so much easier to ask than engineer something.
Bill
 

AMD Rules

Lieutenant Commander
Joined
Sep 23, 2004
Messages
1,707
Re: Water pressure gague

Typically you will find them attached to the NPT fitting in the water jacket cover between cylinder #3 and #4. You may see a plug there now, as in the pic below:


Click to see larger image
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Water pressure gague

When you install the gauge, install a new impeller at the same time. Then note the idle and wide open throttle water pressure readings. In the future, any deviation from these "normal" readings indicates the impeller is degrading. If you don't install the impeller, you really don't know if the numbers you are getting are normal for that engine.
 

Smig

Petty Officer 2nd Class
Joined
Nov 13, 2005
Messages
182
Re: Water pressure gague

What pressure range could you expect to see?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Water pressure gague

That's why I suggested installing an impeller at the same time. No two engines are the same. If you haven't replaced the impeller recently, how do you know its not ready to disintigrate tomorrow? With a new impeller you know what is normal for your engine. I don't know off hand what normal is for that engine. My 75 HP 3-banger runs 8 PSI at idle and 16-17 PSI at WOT with a new impeller. Yours will not likely be the same.
 

Bill Adkins

Seaman
Joined
Sep 27, 2006
Messages
68
Re: Water pressure gague

Smig said:
What pressure range could you expect to see?

Not sure what I'll see, the old gague wasnt even hooked to the motor when I bought it. I will have some time to complete it week after next and then I'll see. The boat stays at our cabin in the local mountains 4 miles from a nice lake.
Bill
 
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