dual water pickups xr bravo
 

I switched my drive last nite on my eliminator cat. The old drive only had a low water pickup. I was told that was because it was a cat hull. The xr drive that I put on has dual water pick ups. Will that cause any problems?

Re: dual water pickups xr bravo
 

If you loose water psi or see water temps climb at speed, then the upper holes are not getting water. You can plug a couple of them, but not too many. Compare the openings in the low water pickup to the dual unit..

Hope this helps
Dick

Re: dual water pickups xr bravo
 

I don't have a water psi guage. The motor is a closed cooling 525. Will it be the oil temp guage to climb or will the water temp guage climb? What do you cover the holes with? Tape?

Re: dual water pickups xr bravo
 

Bringing this one back to the top..

I'm converting from B1s to XRs. I bought a dwp XR, and am now looking at buying a lwp drive. Is one better than the other? Will it matter if I mix and match on my boat? Could the lwp drive be drilled out to make it a dwp drive?

Re: dual water pickups xr bravo
 

I was told that the drive with the single low water pick up was used on cats and the duals water pickup was used on v bottoms.

Re: dual water pickups xr bravo
 

Steve,
My 31 Formula had LWP only, the new 38 has DWP. Haven't had any problems with either (well, not water related anyway)

Re: dual water pickups xr bravo
 

If you need to plug some off the best way is to thread the hole with a tap then put in a threaded allen head plug, then if you want to open back up just remove the plug. Little blue locktite is a good idea also.

If you start to overheat the water should go up first followed by the oil as well.

Re: dual water pickups xr bravo
 

Theroy has it that any openings on the front of the bullet will cause problems with clean water to the prop. That being said, if you run a high X dimension, then you need a low water pick up to solve a problem. When they first came out with the LWP, people were having problems with plugging them. Too much time on the beach enjoying, or shallow water. The DWP helped in that area.
I have a higher X and run the side pickup, I have one or two holes plugged with the above mentioned process... Works for my boat.
In my opinion, I keep away from the holes in the front of the bullet, to help water to the prop to help lift the bow. If you run a cat, that isnt an issue the hull does it for you.
The warning signs that you have a problem are higher water temps at speed and then oil temps go up too. If you have closed cooling I would think the reaction would be much slower.. But once you slow down and start picking up more water the temp will come down..
Each boat will react differently, depending on the hull and setup..

Hope this helps..

Dick

Re: dual water pickups xr bravo
 

Mr Gadgets, Just trying to follow your post, are you saying that cooling inlets on the front of the gearcase are detrimental unless absolutely needed such as a high X-Dimension ( cat hull). I'm running a DWP on an XZ ( V-bottom hull ) and wonder if a side water pick-up would be faster, I still have the standard Bravo with side inlets? Steve

Re: dual water pickups xr bravo
 

Can' Yea or Nae on any of the above! I put a Bravo Diesel X on my 22 it has Hi/Lo pickups, what I experienced was higher water pressure at speed which caused my sea strainer to leak a little. A better gasket cured the leak. On the plus side both my Alpha and Blackhawk drives let a ton of lake weed get through into my strainer, with the dual pickups I hardly ever have to clean the strainer. I believe that is due to the pump being able to split the suction between the two pickups.

Re: dual water pickups xr bravo
 

509,
yes that is the theroy that Hydromotive goes by. Any holes on the front of the bullet cause problems. Wheather or not it will increase speed is up to the boat setup, but that is what they go by. I like their nosecones for the two Checkmates I have owned. That is the only experience I have. But that is what they like.. Will it increase speed and lower drag?? I think so, but have never done any back to back tests. I do know on my old Checkmate with short bullet, I was hitting a wall at 78mph. The hydromotive cone, broke me thru that wall..
Give them a call and see what they have to say..

Hope this helps explain it a bit better.
Dick

Re: dual water pickups xr bravo
 

OK, so it sounds like I'm better off with duals (deep-v Cafe Racer). Now the question is can I drill out the side pickups myself? Seems like the casings for lwp and dwp would be the same, the only difference being getting the holes drills out.

Re: dual water pickups xr bravo
 

Mercruiser bulletin 2001-01 covers this issue in detail.
It states clearly that the dual water inlet gear case may not supply enough water pressure and flow to the engine in high X dimension installations.
I have experienced this first hand on a blower setup where I couldn't get enough water pressure to the motor. Once the upper holes were plugged I had more than enough. The pressure was blowing right out the top holes prior to plugging.

Stainless 1/16 NPT plugs (Merc p/n 22-16581) are used for this issue on high X dimension boats.
I can fax the bulletin if you PM me.
Hope this helps,
Dave

Re: dual water pickups xr bravo
 

Dave,
Good info to know I would like to have that info.. I will pm you.. thanks!

Steve,
I see no reason you cant drill the holes to make it a DWP. But just drilling wont completely do it. If you notice how the holes are shaped on the side pickup, they have little troughs leading up to them. I did some work on my OB lower once. I was told to tilt the troughs downward to better accept the water flowing on the side of the case. So after you drill them, I would grind a small relieve to make a trough to channel the water. And I would imagine you could fine tune it by drilling only a couple of holes and then adding them to suite your needs..

Hope this helps
Dick

Re: dual water pickups xr bravo
 

Dick, Thanks for the reply! I'll have to do a test in spring and see if there is any speed differences between the two styles. When I bought my XZ with DWP, the top half of the side inlet was tapped and plugged already. It was run on a Eliminator with a high X and was sucking air previous to the plugs be installed! Steve

Re: dual water pickups xr bravo
 

I have a DWP XR on my 25 Outlaw with Imco ext box running a high x dimension. I was told to go for the dual pickup despite the high x because it is faster due to reduced resistence. My boat runs over 80mph. The side pickups release excess pressure from the low pickup. It works really good.
I have 4 1/2 inches from pad to propshaft and it would seem that (on a V bottom) the drive has to be even higher before a LWP is neccessary.