I have a new installation of a 502 carb with a Rex Marine Thermostat and crossover with bypass hose and CMI unitops with the elbow bung plugged. I am running the Bravo X dual water pickup and using a SS water strainer to the standard Merc water pump through a large oil cooler.

My question is as I hit 50 MPH my water pressure climbs to 35 pounds as measured at the port outlet on the intake manifold next to the thermostat housing. That seems high for water pressure, faster speeds create even more.

What should my target pressure be and how best to control it with my setup? I talked to CMI and they felt it was not restriction within the pipes standard setup with the standard internal pipe openings ,and felt a elbow bypass added would not neccessarily be the solution.

Sorry if this issue has been answered already, I tried to do a search but I can't get it the search function to work .....

I appreciate any help, thanks Mike

Check this thread. Should give you all the answers.

http://forums.boatfreaks.org/showthread.php?t=9196

did you out holes in the thermostat? 3/16 2-3 holes

Right on

Good ideas thanks! I am going to drill out the thermostat and try the drive shower tapped into the side of the drive trick and see where I am at. If I'm still high I guess I will put a relief valve into the water intake line instead of plugging up the drive holes. This dialing in never stops does it!

Well I installed the CP Performance pressure relief valve between the oil cooler and crossover with the "T" fitting and instantly fixed! I used 3/4" hose to the dump port. I can dial in below 15 pounds max or less if I want or up to wherever, right now I have it at 20 pounds where it hits and holds anywhere above 3,000 RPM.

http://www.cpperformance.com/SearchR...?CategoryID=48

Since my boat had a Superchiller before I just used one of the chiller dumps for an easy plumbing job without any new holes.

Thanks for the input guys ..... nice easy tweak to pamper my new engine.