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How to add a Shutoff Valve to your boat's cooling system

OperationROL

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Since our boats have an open vs. closed loop cooling system, there is a potential of flooding the engine through the exhaust if there is not a positive exhaust pressure pushing out and preventing water from entering there. While underway, and the engines are at high revs, there is no danger of that, but when an engine fails or you are being towed, the risk increases dramatically. Therefore, the owner's manual tells us to operate at no-wake mode to return to port. That way the water is not moving at a rapid rate and is less likely to jet up into the exhaust. However, operating at no-wake speed is painful if you are several miles from port and need to get back because of an inoperable engine. There are many that have shared their painful stories of operating for over 5 hours to get back to port. Since I am inpatient and would be poking my eyes out if I had to travel that far in no-wake mode, I decided to install a valve that would simply cut off the potential for water to enter the engines through the exhaust. Some others carry an automotive clamp or vice clamp with them to achieve the same thing. I worry about the damage the clamps may cause to the hose, so I opted for the valve and I like the clean look and convenience of just turning a valve.


This is actually a very simple and inexpensive mod. The hardest part is working in such a small area, especially if you have big hands like I do. Because of the little space I had to work in, it took me about and hour of work time to complete this project.

Supplies:

2 brass shutoff ball valves (1/2 inch or 5/8 would probably fit tighter)
4 barb fittings (same size as ball valve)
4 hose clamps
1 roll of plumbers tape
1 hose cutter (anything that can make the cut in the hose)
1 6" - 1' piece of 1/2 hose - It may have been 5/8 in so check hose size. (You may not need. This is incase you do not have enough hose exposed after cut to allow the barb fitting to fit all the way before hitting the fitting on the other end of the hose.



1. Locate the hose at the rear wall of the engine compartment at the bottom left of each engine.


2. Cut the hose before the "Y". It is about 4 inches long. If you cut exactly in the middle, you might be able to use the cut hose and not replace it with longer pieces when you are installing the barb fittings.



3. Wrap the threaded end of the barb fittings with plumbers tape.

4. Screw the threaded end of the barb fittings into each end of the valve and ensure a tight fit.

5. Make sure the clamps are in place but loose over the existing cut hose.

6. Insert the barb end of the fittings between the cut ends of the hose. You will know if you need to replace the cut hose if the barb end hits the fitting from the other side and does not fit in all the way. If that is the case, cut a piece of hose long enough to fit the barb fitting without hitting the fitting on the other side.

7. Slide the clamps into place and secure.

 

Julian

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Magic

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Awesome tip! We only had to limp back once, and secured the line with a rag and vise grips!
 
Last edited:

Geiger41

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Any suggested vice grips ? I would assume I would need 2, one for each engine
 

Geiger41

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Ill be ordering them tonight. Not the handiest person so a simple clamp sounds better then cutting 2 hoses!! Thanks for the recommendation. Is there anything else recommended in case an emergency tow occurs ?
 

Britboater

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Warning to Sea Tow members!!!!

I was filling up with gas and a Sea Tow boat was next to me, the pump attendant complimented me on our new boat, so the Sea Tow guy looked over and asked if I had joined. 95 days free with purchase, but I did acknowledge that I will be joining annually.

I then asked if he was familiar with jet drives and the need to isolate the intake, "Is it 2 stroke or 4", "4" was my answer, "no need to isolate then" was his answer :confused:.
 

jawsf16

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It is debateable about what speed would cause problems. I say better safe than sorry.
 

txav8r

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Just to be clear, your manual says you can't tow over no wake speed, without risk of damage if the engines are not operating...but like Jaws says, it is debateable what speed is actually risky.
 

Magic

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In any case, if you flood your engines, its not covered....
 

KXCam22

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After installing my valves I got to thinking ( with some site members ideas) that with the gates held open there should be little or no water pressure built up in the jet housing to force cooling water into the system. Needs to be tested though. Cam.
 

tdonoughue

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That would be a tough one to test.
 

KXCam22

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I think you could just disconnect the cooling line at the Y and see if water came up that far (and how much pressure) when driven on one engine. Cam.
 

OperationROL

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Most people never use insurance, but they sure feel a lot better having it. :D
 

Gym

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Warning to Sea Tow members!!!!

I was filling up with gas and a Sea Tow boat was next to me, the pump attendant complimented me on our new boat, so the Sea Tow guy looked over and asked if I had joined. 95 days free with purchase, but I did acknowledge that I will be joining annually.

I then asked if he was familiar with jet drives and the need to isolate the intake, "Is it 2 stroke or 4", "4" was my answer, "no need to isolate then" was his answer :confused:.
I don't think the Sea Tow driver knew this equipment as there is NO difference between the 2 and 4 stroke engines with regard to water ingestion on a dead engine above no wake speed. Another nice feature of the tow (isolation) valves is the ability to flush your engines with fresh water while sitting in the salt.
 

Andy S

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Another option on the valve placement.

I put my valve between the jet intake and the wye fitting (where the flush line is connected), not between the wye and the engine as shown above. This way when I flush my engines, I close the valve which forces all the flush water through the engine and none leaks out the jet intake. I found for me the best place to put the valve was under the clean out tray, I did not want to reach to the rear of the engine compartment hanging all over a potentially hot engine to operate the valve. On the 2007-2009 models (not sure on other years) the cleanout tray has an access port next to the each cleanout plug. The cooling line for each motor runs directly below the access port. With the valve installed and the access cover removed, I can reach the valve.
 

Murf'n'surf

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Just so I understand correctly.... The water is forced into the square pickup at each drive?
 

MOA_Chaser

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I am adding my valves under the cleanout tray. I had bought brass valves, but am returning them. I found a few dealers direct from China on eBay who sell all stainless steel 3/4" ball valves for $7.40 each. Add in the barb ends, and I'll do both sides in stainless for under $50 total. Buying from U.S. based suppliers, I was looking at $23 per ball valve, and about $15 per barb fitting... $106 total!
 
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