What is the correct engine water pressure at 100 mph?

Its not really speed that you want to calculate, it's more or less engine power, which in this case, if your max speed is 100, then thats near peak power. At peak, typically near maximum rpm, it should be 25-30psi. Ideally you want this at all times, but this doesn't happen, so it needs to be progressive throughout the engine rpm.

Thanks,
Dustin

Gotcha, Thanks for the quick reply!

mine runs 15 to 20

I have heard all kinds of ranges on this question. Mine runs at 12 psi at WOT. Is that too low. If so, what risks am I running at this low pressure. The rigger trimmed the springs on the Mercury release valve and seems ok with this pressure.

You do not want high water pressure. 15- 20 PSI is perfect. That's what I shoot for.

15-20 is what I have tried to shoot for also. Higher that that I get concerned.

Would you be concerned with 12 psi at WOT? I am not in the 15-20 range. If so, I could purchase new springs and start over. I've been running this set up for the past 2 seasons.

mine runs 20-30 dump valves open at 28 ...
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12 is fine