Hey guys I recently replaced my drive with a imco scx and now my water pressure is thru the roof. I tested the boat last night and the pressure went to 45psi. I need to lower the pressure before I go back out. Any ideas would be great. I was thinking of bleeding some of the intake manifold to a fitting on the side of the boat but dont know what size line to use and where would be the best place to hook it up at.
Thanks
John

Just call steve at rpm and ask him how his is done.

he is on vacation this week

To reduce water pressure, we run a -10 bleed line from a 1/2" NPT plug on intake manifold thru the transom. If it is too much, it is easy to reduce in inside of the NPT fitting to increase the pressure. Another option is to increase the water flow thru the exhaust with larger hoses, etc.

You could also increase the pulley size on the pump and slow the pump down which would lower pump pressure.

Best Regards,
Ray @ Raylar

I've seen people modify the IMCO water pick-up's. It rams water up into your engine... I had water pressure issues when I had IMCO Extreme SC's and once I got rid of em the water pressure was normal.

i had the same problem when i switched drives.my new drive has a low water pick-up at the front of the nose cone and that gives the water system more water pressure because of the ramming effect it has.i ordered a pressure reducing valve from cp performance.it all comes in a kit.simple to install and pretty cheap.it is allso adjustable.i was seeing 40 plus psi at wide open.....too much in my opionion.

Mercury sells a water dump that is installed in the hose after the pump. It is a pressure relief valve that runs a smaller hose to the transom or hull side. No need to dump water at all speeds just when it is too much.
Merc
Water pressure relief valve
863208a3

John, I think that this is what Gary Grimes was telling us about????

Right on! I've had great results with this part. It does a great job of regulating pressure. The only bummer is Merc greatly increased the price from what they were a few years back!