water pressure

[rkmirage]

I've been running this set up for 3 years with no issues but, 2.5 200, carbed motor on an opti mid with block offs for the compressor and 200 tuner, Water pressure is 8 to 10 at wot, and 0 at idle. I replaced the poppit and the thermos which had been hollowed. I still have no pressure at Idle, although I have plenty of flow. I've run this motor for 3 years with no temp issues, am I trying to fix a problem that really isn't or am I trying to fix something that as of yet hasn't reared it's ugly head? I've done the Suwannee run, 31 miles each way with no trouble, but something isn't right. What am I missing?

[eli]

I only have 5 lbs water pressure. And 0 at idle. And never see over 140 temp for 16 years

[rkmirage]

I only have 5 lbs water pressure. And 0 at idle. And never see over 140 temp for 16 yearsThanks, I'm not going worry about it anymore!

[Fishinmymission]

We have a bunch of nice gauges in my lab that are all calibrated and they all suck at registering anything below 3 psi. I suggest you measure pump head height to see how much pressure you really have. Measure how high it can pump water up a clear tube.
p = 0.433 h SG (1)
where
p = pressure (psi)
h = head (ft)
SG = specific gravity (https://www.engineeringtoolbox.com/specific-gravity-liquid-fluids-d_294.html) of the fluid (use 1 for water)

[Fishinmymission]

I cant remember the full water circuit but thermos being hollowed probably reducing pressure by allowing water to pass through instead of restricting and building pressure.

[Motv18]

At full throttle merc recommendation iirc is 80-110* head temp. Hot water will of corse raise that.

Typical 2 stroke psi is 12-15 but if temps good ehh.

[eli]

Had my grand daughter drive the boat tonight I watched the temps and water pressure at 100 mph water temp was 135 and psi was 6. There was plenty water exiting motor I could see lake temps in low 80,s