question about raw water cooling system

turtlem1969 · Post by **turtlem1969** » Sat May 22, 2010 11:19 pm

I've got to go thru my raw water cooling system on my f25 and I want to add a way to do a fresh water flushing system for it. Has anyone done this and what would the best way to do it be? Would love to be able to check if the pump is working before I get to the ramp to find out its not working and would also like to be able to flush the system with fresh water when I get home. Any help would be greatly appreciated.

rossjo · Post by **rossjo** » Sat May 22, 2010 11:46 pm

On my 26 trailer queen, I have
A) a 1.5" brass ball valve right at the scupper (you should too, for safety)
B) a T with a reducer to 1" brass pipe, with a ball valves and a hose female connector (with a cap to keep dirt out when not is use)

I can run on the hose this way (open hose valve, close scupper valve)

I also have brass ball valves on the bottom of my 454's exhaust manifold (with extra cost stainless handle), so I can turn each manifold open to drain for winter, and as a quick check to see if water is coming through when the engine(s) running.

turtlem1969 · Post by **turtlem1969** » Sun May 23, 2010 10:14 am

I got the brass valve at the scupper. Was thinking of doing it the same way you described, just wanted to make sure my idea was the correct way to go thru with it.

wowzer52 · Post by **wowzer52** » Sun May 23, 2010 2:11 pm

Some marine supply stores sell a tool that looks like a extendable toilet plunger with a garden hose fitting on the handle which extends from the ground to the bottom of your trailered boat and the plunger end goes over the raw water intake. Turn on the water hose and start your engine. You will be able to run little more than idle because of the limited water flow from the faucet. But it works well for flushing and tinkering on the boat in the driveway.

turtlem1969 · Post by **turtlem1969** » Sun May 23, 2010 7:25 pm

Wowzer- I'll have to look for that contraption.

Today I pulled the raw water pump off because I wasn't getting any raw water circulation. The pump looks like it's not been on there long- do they have a rubber impeller in them that needs to be replaced or what? the reason I ask this is- when I run water back thru the intake hose it washed a bunch of small straight about 1.5 inch pieces of rubber into the strainer, or is this possibly pieces of the hose itself, I need to replace all the hoses for the raw water side, what looked like good hoses on the outside were dry rotten on the inside.

Big D · Post by **Big D** » Sun May 23, 2010 8:42 pm

Did you take the pump apart to get to the impellor? Sounds like you're describing pieces of the impellor blades. You may not have an impellor left!

turtlem1969 · Post by **turtlem1969** » Sun May 23, 2010 8:54 pm

I havent taken it apart yet, wasn't sure if it was like an outboard motor water pump or like the main fresh water pump, first boat I've had with both systems on it, I'll try to take it apart tomorrow, are the impellers fairly reasonably priced or should I be prepared for heart failure?

wowzer52 · Post by **wowzer52** » Sun May 23, 2010 9:07 pm

The impeller needs to be changed about every two years. Some people change them every year and some three to five years. This is off a Ford 351.

turtlem1969 · Post by **turtlem1969** » Sun May 23, 2010 9:23 pm

Thanks wowzer, looks just like mine, same engine also. Looks fairly easy to do. And the pieces in the lower corner look like the junk I pulled out of the pick up screen, probably back washed them down there with the hose. You dont know just how stoked I am to see how easy it'll be.

wowzer52 · Post by **wowzer52** » Sun May 23, 2010 9:25 pm

The impellers are easy to change and can cost 25 to 50 bucks, depending. I rebuilt mine with new housings so they were a little more. When the impeller came apart it jammed up and broke the housing on the inside, $125 each, but usually just the impeller needs to be replaced. Every 2 years can be a good thing.

Big D · Post by **Big D** » Sun May 23, 2010 9:51 pm

BJ, try to back flush as much of the system as you can. Pieces of the impeller may be stuck up stream and cause problems later. If you have an oil cooler, chances are it's the first place raw water passes through after the pump and is where you'll find more pieces. After you've collected all the pieces you can find, try to put the puzzle of pieces back together to ensure you found all of them. If you haven't, they're most likely in the cooling system somewhere and may restrict raw water flow, and inevitably the cooling system's efficiency.

turtlem1969 · Post by **turtlem1969** » Sun May 23, 2010 9:55 pm

I got what appears to be a cooler for the tranny, gonna replace all the hoses in the system, make sure everything is clean, hopefully everything will go better this coming weekend. Also got to replace the toilet, but thats not number one or two on my list right now.

rossjo · Post by **rossjo** » Tue May 25, 2010 12:31 am

Like Big-D says, make sure you back flow out each line and heat exchanger (including the transmission heat exchanger). You MUST get all of these rubber pieces out so they don't cause problems. I always collect them and put them back together to make sure I'm not missing any.

Good to replace impellers every 2 years min - 1 year if possible ...

Oh - and use wire wound hoses in to feed the pump - they will suck closed otherwise!

turtlem1969 · Post by **turtlem1969** » Tue May 25, 2010 9:36 am

got the pump apart yesterday, nothing left of the impeller, and one of the pieces that go across the opening for the water was broken, so I guess I'm going to replace the whole pump, been going thru the whole system one piece at a time. probably should have done all this before I put it in the water the first time. The boat had been sitting for two years before I got it.

definitely going to use the wire wound hoses when I replace them. got to love the learning curve.

wowzer52 · Post by **wowzer52** » Tue May 25, 2010 10:45 am

Turtlem, I will go to the boat today and get you the part number for the replacement housing for your rebuild. This is a one piece housing and comes with a complete rebuild kit, including impeller. It also has a single O-ring instead of gaskets. This will save you a LOT of money and will make it easy to replace the impeller later on.