Wondering if anyone can help me out. Took boat out for the 1st time this year after having some head work done. When I get up too about 3500 rpm the water pressure gauge reads 25psi and keeps climbing if I push it more. Motors are hp500 rebuilt to 540s with Brodix heads. Maybe its nothing to do with heads but its never done this before. Switched the gauges and the same thing happened. I ordered a pressure relief valve from CP Performance but cant figure why this would happen. Also what thermostat should be in these motors. Has 140* in them now and I don't think they are a high flow.
Thanks for any help

did you remove the circulating pump from the engine?

Mike
No not yet. I wondered if I should check that. I don't see any dripping from it or signs that its bad. I did think about pulling the oil cooler as well to look for any debris.
Id hate to go through the trouble of putting a relief valve in and still have blockage somewhere. I'm guessing blockage will cause higher pressure similar to pressing your finger to a garden hose

the reason i asked is the circ pump slows down the flow.removing the circ pump and adding a crossover usually raises the water pressure.

Ohh gottcha. No it wasn't removed. I did blow an impeller sitting on the trailer but all the pieces where right there. I also rebuilt the fuel/seawater pump so not sure if that would cause any problems. Don't really see how.

Just get a new boat.

just get a new face

If there is a restriction, it will be somewhere after the oil cooler. If I get a little debris in my oil cooler, my engine water pressure will go down.