mikeb4

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? Does it sound like an issue with the dual water pickup? should I block off the nose cone?

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

Griff

Target pressure should be 20-25psi at WOT.

I would start blocking off some holes on the DWP drive. Block the top 1 or 2 holes on the sides first and test from there.

mikeb4

Hey Griff ..... I always really liked your water tap off of the drive for the shower supply ... how much of a water pressure drop did you see?? I'm thinking that's one way to take some pressure off and eliminate one more tube dragging in the water on my boat.

tomcei

Mike,
not totally sure about all the factors in you case, but if you increase the size of your bypass line you will free it up. I aggree about the pressure around 20+. I was told not to exceed 23ish.
If you find it a problem increasing the line on the bypass you can drill small holes in the outter rim of the thermastat. It may take 2 or 3 attempts to find the correct hole count to drill but it will work well. You might try starting with 4, 1/8th holes at 12,3,6,and 9oclock. Other wise, go up a number in line size on the bypass.

Griff

I had a hull mount pick up for the engine cooling water. The water going through my drive was just dumping out the side of the boat.
I wouldn't rig a drive shower that way unless you had a separate engine water pick up.