You are welcome. Pulling the drive to see what restrictions there might be there seems like a good idea to me. Also when pulled check to see that the Bravo L/U passage ways are unrestricted if possible like puting a water hose clam shell on it... or?

I hope Cumberland is for fun.

Cumberland was GREAT! The boat ran great. As long as I don't look at the temp gauge there is no problem.:hothead:
It warms up to 160-170 every time no mater what the water temp is or if I'm on the hose or in the water. It acts like the gauge is just wrong. I pulled the temp sensor out today and heated it in some water with a thermometer and it matches what the gauge says. I just don't get it. If it were a flow issue it seems like the temp would very during different conditions. If I didn't have a big enough heat exchanger for the amount of HP then why would it be the same temp at all power settings? I've tried 2 different 120* thermostats.

When you tested the 120F thermostat before by heating in hot water did you monitour the temperature that it opened with a thermometer?

Yes. I even drilled some holes in one of them before I put it back in and it didn't make any difference.

Have you discussed this problem with Dustin Whipple? If not I would suggest you do so.

A couple of things. In talking to someone who has a lot of first hand experience I was informed that it is easy for the sea water intake hose in between the drive and the gimbal housing to be twisted during hose install and the stainless steel replacement plates for the Merc water pump have been known to burn up impellers do to too much squeeze on the impeller sides.

I am going to take the drive off and check the passages. I have checked the hose through the gimble and it looks ok. I may also see about adding a nose cone with a low water pick up.

Is the nose cone supposed to improve sea water pressure/flow?

The one with the low water pickup should. The intake is on the leading edge of the cone. I'm not sure how much machine work is involved in the pluming for the outdrive though.

My old boat (232 mirage with side water pick up only bravo drive) would run 25 psi @ 74mph. I just pulled that motor and installed it in a Nordic rage. I used the same plumbing, exhaust, oil cooler. The Nordic has a dwp drive and the pressure shot up to 40+ at wot.

I think the nose pickup adds a ton of flow at speeds over maybe 65ish. At about 50 it was not a problem for me.

I took it out one time and then added another thru hull to bleed off the high pressure.

Air sucked into sea water system
 

Plane Silly,

Some interesting comments on the effects of air getting into the sea water system including low pressure:
http://www.offshoreonly.com/forums/b...-pressure.html

Hey Tom,

Did you get a chance to check the drive passages?

Your Bravo drive currently has both a low water and a high water pick up, right?

Nope, haven't pulled the drive yet, I'm a lazy bum. My drive only has the side pickups.
The transom water pickup did not work at all, just like I was told. Got to change and impeller on the ramp at the lake.

OK. That is news. If you only have the side sea water pickups on the Bravo drive that is probably the reason for the low sea water pressure as others have atested . I do not know what to suggest to improve the situation w/o low water p/u on the drive.

I am looking at adding a nose cone with the low water pickup. Oddly enough, one of my hold ups is driveway clearance. The drive barely clears my driveway right now and a nose cone may hit.

I have no idea what the differences are between a Bravo drive housing with the additional low water pickup versus the one without the low water pickup. If the only difference is the four holes in the nose of the gear case i.e. there is the same internal passage way connecting the drive's nose to the side water pick ups it would seem that you could just drill the holes. Again, I do not know if that is the case or not.

What I would really like to do is swap out my 1.36 Bravo with just the side pickups for a 1.50 with both pickups.

Sounds like that is what you really need to do given the driveway clearance issue. Two birds with one stone as it were.

How far below the plain of the hull's botton running surface did you locate the water pickup opening? It does not look near deep enough from your picture. Maybe if you converted it to an adjustable water pickup like http://www.cpperformance.com/detail.aspx?ID=1160 or had someone modify your unit to make it adjustable you could adjust it deeper until you get sufficent water versus where you are at currently. You could cut off the current units down tube midway , OD sleeve the two pieces together with a split stainless tube and hose clamps, experiment with the pickup depth and when you find the correct depth have it all welded up permanent. Should be a lot cheaper than a drive conversion.

Bill,
Is that a picture of your pickup?
That pickup is going to run pretty dry sitting above the notch :eek: There's no water there when running :(

Dave

No Dave, That is a picture of PlainSilly's transum that he posted on a different web site. It burned up a w/p impeller first time out. I'm just trying to brainstorm an unsolicited fix to make it work (extend it).

I was going to comment on the placement of the pickup also.. It is not going to work there, even if lowered some. There is just not enough water there once on plane. It should be mounted something like this:

Chris

I did make it adjustable and it goes about 1 inch below the bottom of the boat. Still dry. I'm sure I can make it go lower but as stated above, I think it is pointless due to the pad and the location of my pickup.

Just curious, when you say that you extended the p/u "1" below the bottom of the boat" is the bottom of the boat that you are refering to the horizontal edge bottom of the transum or the boat hulls 'V' bottom if extended out to the pickup from it's recesed position in front of the transum

The bottom of the transum but to the starboard side of the pad.

That, as you probably figured out, is the problem. The working end of the pickup needs to be ~ below the plain of the hulls V bottom that rides on the water in that location and not the bottom of the transum at that location which is of course above the plain of the boat's V bottom hull. The water surface as it exits the V bottom hull will not recover very much from that location when you are at speed. CB-BLR angled his p/u so that it avoids the transum offset entirely and it's working end is below the V bottom hull. If you extend your p/u enough it will pick up the water. A straight edge ruler flat on the V bottom hull parallel to the water flow to the p/u will give you a rough idea how much you would need to extend the p/u if that is what you want to do. Of course this all assumes that the notch ~midway forward in the Rage hull does not extend that far toward the hull's keel to be directly up stream of the p/u which if it is could aireate the water in front of the p/u and thereby reduce the p/u's water flow.

That is not a picture of my boat... but a friends.
I just posted it to show where the pickup should be mounted. It is also not a good idea to mount the pickup near the keel, within the diameter of the prop, so as not to disturb water flow to the prop.

Chris

DUH! I wondered about color difference in your avitar boat and this pic.

Plane Silly?

At this point I just have the transom up as high as it goes and plugged on the inside. Just going to leave it as it is through the drive for now. I may play with it some more at the later on.

Keep us posted when you resume your efforts.