New flush system installed...

mnm99

Well-Known Member
Oct 2, 2015
2,445
Long Island
Boat Info
2004 340 SeaRay Sundancer
Engines
Twin 8.1 Merc
First off , yes I'm a little crazy / anal / Over concerned / OCD...LOL whaterer...I like to tinker and figure stuff out. I wanted to figure out a way to flush my engines with the least effort possible. In the past you have seen my salt away system. That is still inline with the new setup. Here is what i figured out. Last fall I installed a TEE between the seacock and strainer. I connected a fresh water hose to that. With the engines running I tested the water coming out of the exhaust with a Hydrometer. For those that don't know what a hydrometer is it measures salinity. "Salinity describes the content of these dissolved salts and minerals in the water and is measured in parts per thousand (ppt). The easiest and most common instrument to measure the salt concentration in aquaria is the hydrometer. A hydrometer is a device that measures the density or specific gravity of a liquid." The reading from the bay was the same as the water coming out of the exhaust" see picture 32ppm" The second test was with the engine running and the SEACOCK OPEN. I ran the engine for 5 min and did another test with the water out of the exhaust. I WAS AMAZED.. The water came out to 0 PPM!!! I retested the bay water and it was at 34PPM. OK..NOW.. I was concerned about keeping the water on with the engine off and flooding the engine. I pulled the hose off the first cooler after the pump, ran the hose and nothing was coming out. It was just running out of the boat through the seacock. I closed the Seacock and the water came out hard from that hose. That tells me as long as the Seacock is open there is no way to flood the engine. SO here is what I came up with. A Bronze TEE setup between the Seacock and strainer. I ran wire reinforced 1" hose to 2 Bronze valves in the rear locker with hose caps for extra safety. When the engine is running all I do is hook up my hose and open the valve. Fresh water now flushes the engines.. This is so cool, because I can winterize this way too. Just stick the valve hose in antifreeze with the seacock closed and is sucks up the antifreeze...Done...Questions....lol
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Love it. I’m stealing it for my Meridian. Great mod.
 
Well done! (Sharing your source for the parts and a list of items used would be wonderful for anyone wanting to set this up themselves.)
 
Well done! (Sharing your source for the parts and a list of items used would be wonderful for anyone wanting to set this up themselves.)

There's not much to look for. Just make up a BRONZE Tee Using the correct barb for your intake like. I used 1" wire reinforced hose for the flush. Remember the suction will collapse the hose if its not. The valve is just a 1" seacock mounted to the bulkhead. The 2 black hoses just connect to the seacock and a water hose on the other side. I part and pieced it all over just to get the lowest deal. Just gotta search


Discount marine supply .com
SKU: SHI 2500124
Shields 250 Series Water/Exhaust Hose

  1. Specifications
  2. Choose Your Item: 1" x 50': #SHI 2501000 - $186.07 x = $186.07
 
893EAE36-3861-4D9A-8A87-7BB740BF8D8A.jpeg
That looks awesome would love to do something like that do you think that would work with my vertical setup? you seem to have a horizontal set up seacock and strainer
 
That looks like a great setup for FW flushing and winterizing. Did you give any thought to putting a bronze ball valve immediately before or after the elbow coming off the Tee?
 
That looks like a great setup for FW flushing and winterizing. Did you give any thought to putting a bronze ball valve immediately before or after the elbow coming off the Tee?

Yea, I thought about it. Essentially I do, it's just 15 feet away. I would have no reason to use it unless the 1 inch hose had a problem. I may still do it though.
 
mnm99, have you gone away from the saltaway setup and if so why?

No it's still there, It's upstream past the strainer. The salt away dropped the PPT to around 20 with my testing. The fresh water along with it is double protection.
 
Wow, looks great. I really like this idea. Thanks for posting.
 
So a year in, hows the system working?
So now several years in, are you still happy with this set up? Did you make any other modifications over the years? I wasn’t sure but when you test the salinity was the salt away off?
 
So now several years in, are you still happy with this set up? Did you make any other modifications over the years? I wasn’t sure but when you test the salinity was the salt away off?
Yup. Use it every time. I removed the salt away and just use the fresh water flush. The water comes out at 0 even without salt away. Just noticed my elbow was leaking though. I did a pressure test to confirm. I don't think it had anything to do with flushing though. I think I have a cracked weld. Just ordered 4 new ones.:eek:
 
Yup. Use it every time. I removed the salt away and just use the fresh water flush. The water comes out at 0 even without salt away. Just noticed my elbow was leaking though. I did a pressure test to confirm. I don't think it had anything to do with flushing though. I think I have a cracked weld. Just ordered 4 new ones.:eek:
May I ask where you bought the elbows - assuming they are bronze?
Also - what were you thoughts on using 1” hose. Most hoses at dock are 5/8” so would you think that 3/4” would provide enough flow?
And btw- Thanks for the great write up!
 
Thank you for your posting!
Have you checked the salinity in the raw water cooling syatem after the boat sat for a week or two? I always wondered if with such a system the salt water would migrate by osmotic pressure back up the seacock and past the impeller and back into the cooling system?
(I also am OCD)
 
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Thank you for your posting!
Have you checked the salinity in the raw water cooling syatem after the boat sat for a week or two? I always wondered if with such a system the salt water would migrate by osmotic pressure back up the seacock and past the impeller and back into the cooling system?
(I also am OCD)
If you are really concerned about that just close the seacock.
 
Thank you for your posting!
Have you checked the salinity in the raw water cooling syatem after the boat sat for a week or two? I always wondered if with such a system the salt water would migrate by osmotic pressure back up the seacock and past the impeller and back into the cooling system?
(I also am OCD)

Since the pumps are self priming the impellers make a tight seal inside the pump and I would doubt salt water would pass the impellers when not moving.

-Kevin
 
May I ask where you bought the elbows - assuming they are bronze?
Also - what were you thoughts on using 1” hose. Most hoses at dock are 5/8” so would you think that 3/4” would provide enough flow?
And btw- Thanks for the great write up!

Yes - it should be fine while idling for the flush. I have run my 8.1s on land feeding the strainers via a garden hose and I have to trim back the water flow to not overflow the strainer.

-Kevin
 

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