We are making headway....

If you werer going to run a stock pump I have had great luck with the KPM stuff, single stage run dry, they claim it can run dry for 24 hours but I would have to see that to believe it BUT they will last in aereated conditions and it bolts onto a stock pump body. I know you have dual stage mongo pumps already though so I doubt you will be taking a step backwards. I would think the boys at RF would be able to tell you exactly what your boat needs to work, surprised it has gotten this dragged out but hopefully you will get past this and be able to enjoy your ride real soon, good luck, Smitty

Man this has been an ordeal. I went back to when this thread alone started, probably don't want to hear but it's three weeks shy of one year ago.
ed

This may have been answered already, but why is the water being fed thru the drives and not a standard style hull pickup?

The way I understood it from reading this thread is the water is being picked up in both the drive AND a thru hull pick up. Mark from Mer performance brought up a good point, what is to stop the dominant water pressure from flowing backwards thru the other pickup (if thru hull was pushing more water it could push water backwards thru drive or a number of scenarios . His suggestion was to install a check valve or plumb them separately, I would think the RF crew could give instructions as to exactly what the boat needs to work, I can hardly believe that it hasn't been resolved, I bet it is though real soon, Smitty

For some reason unknown to me, you seem to have a problem with the way things are going. I guess it's a damn good thing that the boat isn't yours. I have been up to my ears actually trying to fix not only this boat, but also the dozen others, along with everything else. Unfortunately, I haven't been able to find anyone to pay me to sit around and post nonsense on OSO. I have, however, been in constant contact with Eric (the one that owns the boat, the one that I am looking to please), Reggie and Rick at IMCO. Just because I haven't posted in a few days, doesn't mean that nothing is happening or nothing is being fixed. I feel pretty confident that Eric and Gavin would prefer to have their boat back and be able to ride around enjoying it, rather than reading about it on OSO. We have been working 7 days a week, between 14 and 18 hours a day. That doesn't leave a ton of time for chit chat. This is the first night in weeks that I have been home and sitting down before midnight. The last thing I felt like doing was typing this diatribe.

The other thing is that the water issue isn't the only thing that we are working on. There are quite a few other items that Eric wanted fixed/modified while we have the boat. We haven't spent all the time on the water issue alone. But I'm sure you knew that. We have been taking a methodical and thorough approach to fixing it. Unfortunately, we also have other things to work on. Eric was aware of that when he brought me the boat. He knew that we couldn't dedicate every minute of every day to it. He has been kept up to speed as we speak on a daily basis. If he had a problem with any of it, I'm sure he would speak up.

Although I appreciate any and all help/suggestions, I have somehow managed to get by for 40 years without someone holding my hand. I like to think that I've been halfway succesful as well. I've managed to rig quite a few pretty fast boats that turned out just fine. I welcome any advice or ideas that you may have. What I don't want is the smart ass, condesending horsechit. If you have something to add, then please do. If you have an alterior motive, then take it somewhere else.

Lastly, I have never and will never come on here and post simply for accolades, back slapping, high fiving, etc. If someone wants to offer a compliment, then I will gladly accept it. If not, that's ok as well. The posts that I made and pics I posted throughout the build were done at the request of the owner. I work because I have to. I do this because I love it. I would do it for free (most of the time) if I could because I enjoy it and feel truly blessed to be able to do something that I love.

Now that that is out of the way, let's get to the important stuff. Here is the long and short of it.
The drives were moving very little to no water without the 1" spacers. I don't doubt that the water was backing up from the strainer and going back out of the drives. As per Rick at IMCO, I cut the pickup in the drives back 2". That was a big help as far as water flowing from the drives. They still stopped flowing water above 70 mph. I then cut the pickup another 1", as per Rick. Again, this helped. They have run into this quite a few times with surfacing drives. (They had one instance where there was no water coming through the drives) We had several pressure gauges in multiple locations. The pressure is within 2 psi anywhere in the engine. We put a gauge between the pump and oil cooler, between the oil cooler and block, in the block, in the thermostat housing, etc. They stay within 2 psi, so there is no problem with the plumbing or rigging of the engines.

We also put a gauge in the strainer. With the bypass hooked up, the strainer would never build any pressure. The bypass would constantly dump off water whenever the boat was on plane. We then blocked off the bypass, The strainer made 3-4 psi until about 70-75 mph. At that point, the pressure dropped to 0 and stayed there. That means that we are pulling all of the water from the strainer. That leads us back to a supply problem. The drives are still helping somewhat at higher speeds. When the drives were disconnected from the strainer and only the pickup was supplying water, the pressure would drop the faster we went.

The water pickup has a 1.75" OD. That gives it an ID of just over 1.5" . However, it is stepped down to a 1.25" hose going to the strainer. Also, the fitting coming out of the pickup is brass. Brass fittings tend to be thicker than comparable SS fittings to be strong enough. So that makes the ID a little smaller on the brass fittings. That brass fitting has an ID of 1.035" That is the smallest part of the system and is the restriction as far as I can tell. Combine that smaller fitting with the drives not helping out a ton and you have low water pressure. The drives were offering quite a bit more help with the 1" spacers installed. Not so much with the spacers out.

Currently we can only make a max of about 18 psi. However, it will hold that pressure now. It wouldn't do that before we opened the pickups in the drives. THe problem is that we have restrictors in the tails to help build some pressure. The problem is that not enough water is going in the tails and they are turning on top, since they aren't filling completely with water. The tops of the tails get pretty damn hot. We need more water in the tails, but if I pull the restrictors, then the pressure goes away.

So, at this point, this is what we are doing. We are putting a larger fitting and hose from the pickup to the strainer. It's going to 1.5" hose with high flow SS fittings. If we can't get any positive pressure in the strainer, then we will keep having water pressure issues.

Now, before anyone says anything, let me clear one thing up. When the boat left FPM, the water pressure was fine. At that time, the testing was done with 1" spacers. The pressure was higher then. However, the boat was slower. Eric doesn't want to give up the speed. So, we have to make it work. I'm not blaming anything on FPM, so please don't take it there. They have been there if/when I need them. Eric chose to bring the boat to me since I am quite a bit closer than FPM. I am in no way throwing FPM under the bus.

Forgot to mention that we also used a regulator and a liquid filled pressure gauge to verify that the pressure gauges in the dash are reading correctly.

Think that covers it. We will have the fittings in the am. As soon as they go in, we are heading to the lake. I will keep ya'll posted.
Eddie

Great post Eddie, on all counts.

Well put Eddie.

Great info Eddie , now i feel better that I have the same dia pickup and my plumbing is already set up 1.5 dia right to the strainer , I was worried that he had a strainer problem . I would of thought that with a keel pickup we wood have mega pressure .

Good post Eddie!