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

[Gym]

It's not like it would be a difficult design change for Yamaha to do. All they'd have to do is run larger diameter hose so that the restriction caused by a larger diameter ball valve would end up with the same flow resistance as the original smaller diameter hose without a ball valve.

 

[Gym]

Many ball valves are called "full bore" so a 3/4 ball valve has a 3/4 opening. You could also adapt up to a larger size valve to prevent any restriction. I've had my 5/8 valves installed for 4 years now with no issues.

 

[MrMoose]

Many ball valves are called "full bore" so a 3/4 ball valve has a 3/4 opening. You could also adapt up to a larger size valve to prevent any restriction. I've had my 5/8 valves installed for 4 years now with no issues.

The fact that any connections are made via barbed fittings that fit inside the original hose always results in decreased cross-section and hence decreased flow.

 

[xoomer]

You have to do what you are comfortable with but these valves have been installed on many boats over the past few years that I've been following these forums and I don't recall anyone complaining about an over-heating problem caused by the valves. In any case, shouldn't the overheating warning come on before any damage is done?

As far as Yamaha goes, since they don't know if these valves would cause a problem or not I'm not sure they would have a real case against them--of course they may automatically deny any claim for a blown engine for any reason, that wouldn't surprise me. ( I suppose you could always take the valves off in a few minutes and re-install the original hoses if that were a concern after any engine trouble.)

If I were in fresh water I probably would only use the clips but since I only am in salt water and keep my boat at an indoor storage I need the tow valves because I want to do my own flushing before the boat is lifted out of the salt water--I don't trust the guys who work there to do the flushing correctly.

 

[OperationROL]

You have to do what you are comfortable with but these valves have been installed on many boats over the past few years that I've been following these forums and I don't recall anyone complaining about an over-heating problem caused by the valves. In any case, shouldn't the overheating warning come on before any damage is done?

As far as Yamaha goes, since they don't know if these valves would cause a problem or not I'm not sure they would have a real case against them--of course they may automatically deny any claim for a blown engine for any reason, that wouldn't surprise me. ( I suppose you could always take the valves off in a few minutes and re-install the original hoses if that were a concern after any engine trouble.)

If I were in fresh water I probably would only use the clips but since I only am in salt water and keep my boat at an indoor storage I need the tow valves because I want to do my own flushing before the boat is lifted out of the salt water--I don't trust the guys who work there to do the flushing correctly.

Well, you may have noticed that I started this thread. However, I have since changed my mind about the valves for the same reasons some suggested. In my former SX230 the valve did prove to be the source of an overheating issue. Well the issue is not actually the valve, but it is a major contributor. The issue is that over time, the cooling system probably ingested some sand and other particles. For the first 6 years, there was not enough to cause an issue, but in the 7th year it did. The cooling system is sensitive to water-flow and just that little reduction coupled with sand and other particles in the system caused the overheating issue. When the valve was pulled out, the overheating issue went away. In the current 242 LS, I do not plan to install valves, just use vice grips.

 

[Smassey22180]

If 3/4" pex fits then I may try this. 2 for $16. http://www.homedepot.com/p/SharkBite-3-4-in-Plastic-PEX-Barb-x-Barb-Ball-Valve-2-Pack-24607A2/206133154

 

[xoomer]

If 3/4" pex fits then I may try this. 2 for $16. http://www.homedepot.com/p/SharkBite-3-4-in-Plastic-PEX-Barb-x-Barb-Ball-Valve-2-Pack-24607A2/206133154

@Smassey22180 I think if I were you I would spend a few dollars more and get the valves which were made for this purpose from Island Racing--they are made so they don't restrict the water flow. One warning, if you get these valves buy bigger clamps because the ones included are hard to work with since they barely fit around the hose. Also, if there are any kinks because of the way the hose has to be installed, get a hose that is wire-reinforced.

BTW, is your hose 3/4"? Mine was 5/8".

 

[KXCam22]

I have the tow valve but wouldn't install them again. All you have to do is have the reverse gate open when towing. Then it is impossible to build up sufficient water pressure inside the jet housing to push water through the cooling system. The real bonus of the tow valves is that when I run my engines on the hose in the driveway, closing the towvalves allows enough water to stay in the system to have water run out the pee holes. Cam.

 

[swatski]

@KXCam22 That is a very interesting piece of information, never heard that before but it does make sense.
Is this tried and true, or more a theoretical consideration? (either way - very cool and useful if in a bind)

 

[xoomer]

I have the tow valve but wouldn't install them again. All you have to do is have the reverse gate open when towing. Then it is impossible to build up sufficient water pressure inside the jet housing to push water through the cooling system. The real bonus of the tow valves is that when I run my engines on the hose in the driveway, closing the tow valves allows enough water to stay in the system to have water run out the pee holes. Cam.

I'd be afraid to try that since Yamaha specifically says not to tow at greater than no-wake speed. It may work, I don't know, but if you did damage an engine by flooding it I doubt the warranty would cover the repairs. I think I would at least carry something to clip the hoses if I needed to be towed.

For me I need the tow-valves so that I can flush the engines with fresh water while sitting in salt water where I do my boating. I can't rely on the guys at the marina--who lift the boat out of the water and normally do the flushing--to flush the engines properly.

 

[KXCam22]

Salt water flushing it probably the best use for them ever. It allows you to fill up the cooling system while flushing/running on the hose. I think yamaha is doing the CYA as if you towed fast and FORGOT to put both throttles in forward, the buildup of water pressure could cause problems. It would be good to know at what cooling water level/pressure water could enter the engine -nice to understand the mechanism. On the lake water flows nicely out the pee holes but not into the engine through the exhaust. On the 65psi garnden hose I cant get water our of the pee holes so I wonder if it really could make it to the exhaust. Towing, I doubt that you could reach even 10psi in the jet housing with the reverse gate down. It would be a nice thing to understand. Cam.

 

[Gym]

I have the tow valve but wouldn't install them again. All you have to do is have the reverse gate open when towing. Then it is impossible to build up sufficient water pressure inside the jet housing to push water through the cooling system. The real bonus of the tow valves is that when I run my engines on the hose in the driveway, closing the towvalves allows enough water to stay in the system to have water run out the pee holes. Cam.

I would theorize that because the intake grate is larger than the nozzle outlet some back pressure is inevitable even with the reverse bucket in the forward position. The greater the speed the greater the back pressure. I do believe you would have to travel significantly above "no wake" speed to force water into the engine though. I know I wouldn't want to test this theory as I'm sure Yamaha has. No manufacturer would want to publish limitations on their product needlessly.

 

[Hannibal]

Interesting thread. I thought the same thing about the reverse bucket in the open position. Good point GYM. Wife ordered a hose clamp vise grip plier.
If I had a twin engine boat and time to play around with it, I might disconnect a cooling hose at the Y, ease around the lake with the connected engine and see what speed is required to simply push water up out of the hose of the disconnected engine at exhaust manifold level with the bucket up and down. Since it's water getting into the exhaust valves that's a concern, it wouldn't take much pressure. Just enough to put water there.
I would have thought Yamaha would have addressed this potential problem a little better. I've seen commercial tow boats towing boats in the intercostal. They are not inching along at no wake speed.

 

[Marvin willis]

Your right I've seen boats towed at a faster pace. I have shut off valves. And Have run 22-25mph on one motor

 

[Buckeye Boater]

This is what I see in the back of my AR192's engine compartment, would I pinch behind this T when being towed?

 

[buckbuck]

That is correct @Buckeye Boater
The hose the comes from the stern (top one in your picture) is the cooling water supply line from the jet pump.

 

[Bryan mazanec]

I purchased some pinch clamps as well. Last weekend was showing someone the engines of my chap and realized they already had inline shutoffs and a warning above them reminding me to engage them prior to towing.

I guess I should have looked around the compartment better.

 

[Jgorm]

Good thread! I just ordered the pex universe valves linked earlier. I was also thinking that you could attach a short length of garden hose to the stock flush fitting and have it dump overboard. This would relive the pressure. I was also wondering if it's possible to over pressurise the system of you shut off the valve and have high house pressure. Someone posted measurements up to 25 psi at wot. I'm wondering if that stupid quick fitting has a tiny hole to address this. I was thinking about installing a hose bib valve at the end of the flush hose, but was worried maybe you could add too much water and pop something. My house pressure is 120 at my hose.

 

[Liveto99]

I think Sea Tow meant the 4 strokes don't have problems. But we know they all do...

 

[gmtech16450yz]

Good thread! I just ordered the pex universe valves linked earlier. I was also thinking that you could attach a short length of garden hose to the stock flush fitting and have it dump overboard. This would relive the pressure. I was also wondering if it's possible to over pressurise the system of you shut off the valve and have high house pressure. Someone posted measurements up to 25 psi at wot. I'm wondering if that stupid quick fitting has a tiny hole to address this. I was thinking about installing a hose bib valve at the end of the flush hose, but was worried maybe you could add too much water and pop something. My house pressure is 120 at my hose.

I'll have pressure data for you guys soon...