Plane Silly, anything new?

Still haven't had her in the water yet. I did block off the top 2 sets of holes on the drive water inlets so that's what I will be checking first. I'll let you know.

Hey Plane Silly, any new test results on your Rage?

Well, I took a water press reading at the raw water pump right where the sensor is and it sure seems low. At 50 mph it was only about 10 psi, at 80+ it did get to around 22 psi. Motor still runs around 170* even though I have a 120* thermostat. And yes I have replaced the thermostat and tested it in hot water. Still seems like I have a flow issue.

I was concerned that the 43psi+ sea water pressure I get at WOT (5800 rpm) was incorrect, so I have been asking around a lot. Bob at Dana Marine did not know what was the normal pressure for the 496 but called a guy that installs a lot of Dana exhausts on Mercs and tests water pressure on each install. He stated that Merc rates that system from 38 - 50 psi at WOT (5100 rpm stock) so my 43 psi at 5800 rpm is normal and maybe on the lower end based on max rpm for stock 496HO's.

What rpm's are you getting the 10 psi and the 22 psi at?

22 psi was around 5000 rpm and don't recall 10 psi but I think it was around 3500.

For reference with the stock sea water plumbing my sea water pressure is 22 psi @3500 rpm, 41 psi @ 5000 rpm and 2-3 psi @ idle.
With the recent addition of a 5/8" dia sea water dump hose 'T'd' into the out let side of the oil cooler water hose (to increase cooling water flow rate through the oil cooler) the sea water pressure dropped to 15 psi @ 3500 rpm and 30 psi @ 5000 rpm and 1.5-2 psi @ idle.. Sounds like yours is low for the 496HO. My coolant still stays in the 140F's during WOT running even with the addition of the water dump hose.

How many hours/seasons on your sea water pump/impeller? Ever get into sandy/muddy water with the lower unit? I understand that the stock brass body water pump can get chewed up pretty quick if sandy water runs through it.

I have rebuilt my sea pump with the stainless plate and new impeller so it should be good. I have a big event at Cumberland this week so I may just leave things alone right now but it is looking more and more like I am going to have to install the transom water pick up.

I figured that you probably had. Well logic would seem to say that if your water pressure is that low at the rebuilt water pump output it has to be between the Bravo and the pump because restriction down stream of the pump would show higher pressure at the pump and lower down stream of a restriction.

I probably mentioned it before but I have been warned by one very experienced person that steped hulls (Heat) can have aireation problems with transum water pick ups that also result in cooling problems. Hopefully someone out there has a proven successful transum pick up mounting location for a Rage. Good luck and keep us posted.

Thanks for all of you input Rage. I don't want to put the pick up on but I am running out of options. I may pull the drive off and see if I can find some kind of restriction.

Thanks again,

Tom