blue thunder

I would like to replace the stock belt driven bravo sea pump (plastic) with something that will move more volume. First off, does anyone know the gpm of the stock merc pump? Second, is there a standard belt driven replacement pump that will move more water and what capacity would it have? Lastly, could the stock merc pump take the higher rpm of changing drive pulley to a smaller pitch? I run closed cooling so excessive water pressure is not a concern.

BT

marinetrans

Try a thru transom water pickup. I know it will give you more volume.

blue thunder

Hey, thats a good idea I do run out of a tidal, low water marina though. Could be an issue with sucking up mud. I ponder that, thanks.

BT

f311fr1

West Marine carries a all bronze body replacement pump that can be mounted with either the Merc hi-performance mount or the stock three bolt mount. I have used them on 540 CU IN blower motors and 598 CU IN N/A engines with good results. You can also use the Eickert or Hardin dual impeller pump for more flow, but the water passage in the Bravo is to small, so you need a sea strainer and external water pick up.

Ted G

iTrader: (1)

You know, the stock pumps push a lot of water through. They will cool 800 HP with no problem. You may want to try the transom pickups and see how that works. Are you actually having a problem with temps?

Wally

iTrader: (1)

the stock pumps with the right size hose attached and no restrictions will pump huge amounts of water. I work for March pumps here in IL. The dept i manage makes the pumps for the Marine Air A/C systems that just about any boat with A/C has. We did a test of the merc sea-water pump here on the test tank we have in house. We were looking into possibly making a rubber vein impellor type pump in our product line. We hooked the Merc pump up straight shaft through a collar to a 3hp elec motor. One of the first tests we did was to see how much power it would take to trun this pump over.....The 3hp couldnt do by itself without some help getting the pump turning....unfortunatly we didnt have any of our bigger pump motors avail at that time. Anyway at 3000rpm this pump is capable of pushing over 100' of head height!!! I dont recall what the GPM's were cause we did this test about 2 yrs ago but i can say that cooling should not be any problem as long as you have a good water supply and a good impellor in it.

blue thunder

Not having a problem insptech, just wanting to move more water throught my exhaust and possibly improve oil temps. Right now I have to run engines with no tstat in coolant to keep oil temps in check. I believe more flow would help. not looking for pressure, just flow.

Thanks for the ideas

BT

Smitty

iTrader: (1)

If you are having oil temp issues then you need to upsize the oil coolers. That should take care of the problem.

WETTE VETTE

I bought a replacement housing / impellar from KTM. It comes with a 1 yr warranty against impellar failure and pumps more water than the merc. I used it this season and it works very well. It requires some modification of the stock drive. Here is a photo of the unit.

blue thunder

I already run large coolers Bigw. 3x16, 3x22 w/ps Eddie Marine. I believe the problem lies in the fact I run closed cooling. The engine heat exchanger causes more restriction than running without. Maybe I should buy heat exchangers with larger tubes... hmmm.

How much was that pump Wette Vette? What needed to be modified to make it work? Did you get a noticable increase in flow out the exhaust? That is what I am after.

BT