High Water Pressure?

[joeim8]

Ok guys piggy backing off of a previous post, The only issue I seem to have left is high water pressure which eventually alarms at WOT.

I have a 2002 Merc EFI 2.5L 200hp (SN#0T443994)

I recently put a reman powerhead in and during the breakin period noticed the high water pressure reading on the gauge which may or may not be exact as it doesn’t 0 out at off position but I went ahead and purchased a VesselView to confirm the alarm at WOT was indeed related to water pressure and here is the fault I received:

”Block coolant pressure”
”The input circuit for the sensor is above valid limit”
”Water pressure sensor is not working properly”

Also though the gauge on my boat maxes out at 30 psi the VesselView said I was almost reaching 40psi at WOT.
Engine temp seemed to be fine as it was in between 120-135 mostly.

To this point Ao have inspected brand new poppet, installed and tested brand new thermostats, installed new water pump kit, inspected water pressure sensor lines or the small line eventually connecting to it for clogs all of these items seem to be working properly so I am pretty confused at this point?

My only other guess would be the sensor itself, my question is could there be anything else to inspect? Might there be something in the midsection a gasket or line that could be causing this issue, looking at the parts diagram there’s just not much left that I know of??

What do you guys think?

[leonreno]

If I understand correctly you have a analog gauge that doesn’t zero when motor is off? And know vessel view says high pressure? I would pull tube off block and blow it out and then replace the analog gauge and see what it measures. I do not know how the vessel view gets its reading, is the sensor screwed into the block or does it fit into the same tune as the analog gauge? But first get a working analog gauge to see if you do indeed have high pressure. You could also buy a cheap water pressure gauge at the hardware store, the kind used on ag or garden water pumps and tanks, usually less than $10, and get a barb fitting that fits the small tube off the motor. I used one to verify my pressure readings were correct as I was getting high pressure on a new pump, but after pump wore in a little, pressures were normal. But mine were not as high as yours.

[joeim8]

Thanks for the reply Leon.

Which tune are referring to, that I should pull and inspect?

Do you happen to know the part# for the gauge?

[leonreno]

The tube that goes to the analog pressure gauge, I believe will be connected to the block under the starboard head. it’s a small rubber tube that the pressure gauge uses to measure water pressure.

[joeim8]

Ok yeah thanks Leon I have removed that line and inspected all good.

Would a bad water pressure gauge actually trigger the alarm I posted?My thinking probably flawed was if I just purchased the vessel view I could get an actual readout and kind of bypass the gauge because I wasn’t sure that it would trigger the water pressure alarm anyway, to my surprise the vessel view showed even higher than the gauge which maxes at 30psi.

Anyone have a part number for what gauge I would need, hopefully this is it because I’m stumped at this point.
Boat is a 96 Ranger 391v if that matters for gauge at all, motor lusted above.

[Rip Bass]

I remember reading about some kind of exhaust gasket leaking and adding boost to the water pressure but I don’t recall exactly what it was. Maybe Mr Leon or Mr Weed will know more about it.

[shuddyssoup]

Poppet valve is perhaps stuck ?

[sleeper bird]

I remember reading about some kind of exhaust gasket leaking and adding boost to the water pressure but I don’t recall exactly what it was. Maybe Mr Leon or Mr Weed will know more about it.

might be my post about a head gasket leaking and causing a high water pressure reading,and an alarm at idle.

[joeim8]

Popper valve seems ok.

Interesting regarding an exhaust plate gasket, would that indeed cause high water pressure of bad?

So far I have replaced and or inspected the poppet valve, thermostats, water pump kit, inspected water pressure sensor lines and tell tale all seem good.

i have on order a new water pressure gauge and water pressure sensor, I though these would be the last two things left that could cause high water pressure but can anyone further elaborate on any kind of exhaust gasket that could as well? Or snythjng for that matter.