Water pressure relief valve question

[cutwater]

MOP, BigGrizz, others...

Who makes a good water pressure relief valve setup? I am running a raw water cooled 350 with a lower unit water pickup. I sometimes wonder about my risers' ability to keep up with the flow from my outdrive. I think it's about time for new exhaust anyway, but it shouldn't hurt to use a relief valve no matter what setup I go with, right (circ pump, crossover, etc)?
John

[VetteLT193]

It shouldn't hurt. Merc makes one, I'd probably check around for that one first unless others know of a better unit.

You generally have to pop another thru-hull in the transom though. I know some people that dump it over the drive, makes a semi drive cooler.

[BigGrizzly]

Garry Grimes designed the one Merc sells. It is expensive and used a big overflow. IT was designed for real high performance application, 100mph big power boats with transom and hull pick ups. Unless you are running 80s it will probably not be an issue. Just put on a pressure gage and make sure it remains below 35psi. when I closed cooled the Criterion I removed , sold it to a friend no need now.

[zimm17]

hardin marine makes one. I'm using it to feed my intercooler once the boat is up on plane.