Water pressure question on merc.

[Edwardbowen]

I have a 1999 Mercury XR6 150hp.
Sn# 0G883085
Last week I had an overheat issue so I decided to change thermostats, poppet valve and add a water pressure guage. The guage is installed at the top of the block about 3 Inches from top of block using a Tee fitting. I ran in the driveway using muufs and garden hose but idle pressure are mid 20s a d hi idle pegs guage. Water from the tell is warm enough to allow you to keep your hands in stream without getting burnt. Block is nice and cool to warm. My question will these number change when boat is in the river and prop engaged? Book says need to be over 12psi WOT and 1 to 3 psi at idle. What am I missing? Thanks

[leonreno]

It’s not abnormal for the pressure to be higher with a new pump, it normally will settle down after running it the first time. However you should monitor it and the temp to make sure the thermostats are opening correctly along with the poppet valve.

[Crappie Bob]

What else does the T fitting service? I don't think a gauge line should be hooked to anything but the gauge to get proper readings, at least mine is that way. Maybe wrong, some of the boat mechanics can clarify..

[Edwardbowen]

Per everything I read and found on here that year did not have the tap for water pressure and suppose to connect via a tee fitting as close to the top of block.as possible.

[Edwardbowen]

Ran it.today and it ran good however the pressures are high. Will thermostats cause high pressures then normal? If so I can always pull the new ones out and test them.

[leonreno]

They will cause high pressures at idle, make sure the aren’t backwards. You put them in a pot of water and heat them up with a thermometer in the water, they should start opening at 143 degrees and be fully open at around 160 degrees. They really wouldn’t cause high pressures at wot becauthe poppet valve takes over at pressures higher than 9 psi.

[Edwardbowen]

They cannot go in backwards. I think I will check thermos just in case. I will try another pressure guage right at the tee and see where that leads me.

[Edwardbowen]

I just pulled the new thermos and tested. One opens at around 140° but the second one opened before 120°. I also check the origional and they opened at 140°. I put the origionals back in until I can get 2 new ones. I still need to check the pressure with another guage.

[Spencer2]

You may have blockage inside the block. If you pull the exhaust divider plate you can see the water passages that go through the divider into and around the cylinders for cooling. Small rocks and other debris can get lodged in there causing high water pressure and heat issues.

[Edwardbowen]

This evening I tried 2 other guages and they all read the same. Pressures are the same as per earlier. Here is where I installed the tee fitting. By the way how much pressure can these pumps produce. I thought only 19 or 20 psi at most but o viously I was wrong on that one.20220502_182338.jpg

[Edwardbowen]

This is another view. Goes from top of motor down behind coils to poppet valve.20220502_182941.jpg

[Crappie Bob]

The thermostats come 120 deg and 143 deg, I don't know why you have one of each unless they are supposed to be on the V blocks.

[Edwardbowen]

Mistake from manufacturer. Should be 2 at 143°

[JOE54]

+2 @143, you have a restriction in block remove poppet valve pay close attn to gromett s/seal that is pressed in block must be installed flush with inner edges or it will restrict , stem should slide in seal butter smooth , your gage is installed correctly please put raidius tie straps on hose to gage at connection at tee

[Edwardbowen]

Thanks. I will check out the seal in poppet

[JOE54]

hurry up there biting

[Edwardbowen]

Good call Joe. The carrier popped out of its seat. I did not originally replace the carrier when I did the poppet. The carrier and grommet pulled out together. I installed the new carrier and reused the grommet. Pressures at idle are around 3 psi was not able to ramp up to full throttle but I did take it to 10 psi then right back down to idle and the pressures followed. Now my last question.
Is it normal for water to come out of the weep hole on the poppet valve assembly while running?
Thanks again. This has definitely been a learning experience.

[JOE54]

NO , take a punch and stake that grommet in block ;;;;; tip of punch on block you fixed it yeaaaa

[Edwardbowen]

Hey Joe is it normal for the weep hole to the poppet to have water coming out? I know in an auto water coming from weep hole in waterpump is not a good thing.

[JOE54]

no , no leaks