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

[Englewoodcowboy]

Just something to add to this thread for the DIY'ers. I am getting ready to do this mod and finding a 5/8" barb locally is a PITA. I have found 3/4" PEX valves which is a 3/4" barbed ball valve with a full port configuration. A lot of ball valves actually reduce the port by as much as 25% so you need to pay attention to what you are getting to avoid over heating. The PEX valves are brass construction with stainless ball and handle which is ideal for marine use. Here is a link to get them for $4.50, way cheaper than anything else I have seen. http://www.pexuniverse.com/3-4-pex-brass-ball-valve

 

[Murf'n'surf]

Just something to add to this thread for the DIY'ers. I am getting ready to do this mod and finding a 5/8" barb locally is a PITA. I have found 3/4" PEX valves which is a 3/4" barbed ball valve with a full port configuration. A lot of ball valves actually reduce the port by as much as 25% so you need to pay attention to what you are getting to avoid over heating. The PEX valves are brass construction with stainless ball and handle which is ideal for marine use. Here is a link to get them for $4.50, way cheaper than anything else I have seen. http://www.pexuniverse.com/3-4-pex-brass-ball-valve
View attachment 25910

So the hose will have enough bite on these?

 

[Englewoodcowboy]

@Murf'n'surf They should, I just ordered a set and will verify when they arrive but by what I have found the barb is almost 1" in length, we only need a hair over 1/2" for the clamp to do its job. I also like this as it eliminates any plastic as well as additional joints, another project I am undertaking, no more plastic penetrations below the water line.

 

[aarons1k]

Which hoses do u install the valves on ??

 

[Scottintexas]

on page one there are pictures, the general vicinity is the lower rear of the engine, starboard side
if you want to shut all water to the engine put the valve on the forward side of the "y" joint,
if you want to be able to run the engine and flush with fresh water or put the valve under the cleanout tray it goes aft of the "y" fittting

 

[Scottintexas]

@Aaron Stammet also check out this video from the faq, it really helps to understand how your engine cooling works,
https://jetboaters.net/faq/how-does-the-cooling-water-flow-in-my-yamaha.101/

 

[aarons1k]

@Aaron Stammet also check out this video from the faq, it really helps to understand how your engine cooling works,
https://jetboaters.net/faq/how-does-the-cooling-water-flow-in-my-yamaha.101/

l

Thank you ! Got it now

 

[Englewoodcowboy]

My valves arrived today and 3/4" PEX is actually a 5/8" barb so it looks like these will be a perfect fit for tow valves. The barbs are 5/8" long and 5/8" OD.

 

[Gym]

On my valve install I covered the valve body with foam pipe insulation fastened with tie wraps to keep the valve from bouncing around in the lower bilge.

 

[Englewoodcowboy]

I finally received my correct hose clamps. Notice that these have a skirt to keep the hose from getting chewed up. I would recommend this style above any other when dealing with something that is below the waterline. They only come by the box so they will also be used in my ballast upgrade.

 

[Englewoodcowboy]

I finally got around to starting the tow valve install. I started with the port main since it was the easiest to access and would lend itself to the trial process. I started by removing the clean out tray.

Then I looked at the cooling inlet line and decided it would be easiest, since my valve would need to be placed close to the bulkhead to be in reach through the clean out tray access hatch, to cut the hose near the bulkhead and pop the other end off and get a start with it outside of the boat.

Here is the valve installed on one end of the hose. I also have pics to see what a full flow this is in this install with the PEX valves, damn near zero intrusion and full flow so no worries at all with cooling flow restrictions.



This is where it got difficult, I tried silicone spray and fought and fought and bled and now I itch and in the end I finally grabbed my trusty HF heat gun, warmed the hose up a bit to the touch and it slid home like butter. I just paid the dumb tax for everyone to save on fiberglass splinters and bloody knuckles and lots of choice words so pay attention... heat is your friend.

Here is the final result of the port side. Clean install, looks factory and is in an easy spot to quickly access if need be without being a contortionist.

Now I intend to do the starboard main the same way however to gain access I need to pull the water box which means I need to get help for an afternoon from one of my smaller friends who can get in back and release the clamps. While the box is out I will also take that time to install the secondary bilge pump which I do not have at this time so it will be a winter project. I am hoping with my current work problems I get them sorted where I am confident again to start buying other items because it would also be an excellent time to add my through hull transducer as well as set up for the raw water wash down I want. Only time will tell but for now you guys can see how well the PEX valves lend themselves to this modification.

 

[tdonoughue]

Heat! A good idea. Wish I had thought of that. I just pushed and pushed and pushed and used pliers and fingers and pushed some more. Twas not fun. That heat gun trick is awesome.

 

[xoomer]

Just a follow-up on my installation which has hoses running to the front of the engine compartment. I noticed that on one hose, at the back of the engine compartment where it connected to the "y", there was a small kink due to the 180 degree turn it made. It probably didn't matter since I had sufficient water flow from what I could tell, but I decided to replace that particular section with a 5/8" exhaust hose from West Marine which has a reinforcing wire inside and will not kink. If I had it to do over again I would probably use this type of hose for the entire installation--although it is rather expensive being around $10 a foot.

 

[Paul N]

New and first time owner here...so be kind......during the flush out should there be some water flow over the pump intake to help cool that portion of the circuit?

 

[Scottintexas]

@Paul N glad to have you on board,

when you say "water flow over the pump intake" are you talking about the intake grate area forward of the impeller or the intake filter screen behind the impeller where the water enters the cooling system?

either way nothing in the jet pump system needs water for cooling, check out this link from our FAQ about how the cooling system works, it's for the MR1 engine but it's basically the same for the 1.8L
https://jetboaters.net/faq/how-does-the-cooling-water-flow-in-my-yamaha.101/

 

[itsdgm]

@Paul N welcome. The water flowing back into the pump area is essentially back flushing the cooling system. There's a screen at the water inlet that could get clogged with debris. So it's a good idea to make sure that water is flowing back there making sure that the screen is clear. Some guys that have low water pressure on their garden hoses block the inlet line while flushing to redirect all of the garden hose water into the engine to prevent overheating.

 

[Gym]

New and first time owner here...so be kind......during the flush out should there be some water flow over the pump intake to help cool that portion of the circuit?

Welcome aboard @Paul N. There are a few water outlets where you will/may see water during the flushing procedure. You will see water coming from the outlet by the jet nozzle & from the exhaust outlet. You may see water coming out of the pee holes on the rear, starboard side of the boat depending on the engine rpm. Ask away with any questions as we were all new at this at one time. Just remember when flushing...engine on, water on. Water off engine off in that order. This is to prevent possible engine damage.

 

[MrMoose]

Ok, so I've given this topic lots of consideration. I like to prepare for the worst, within reason; everybody has their comfort zone. I have a masters degree in chemical engineering, and I know that installing a valve will always create a resistance to flow relative to a no-valve scenario. In this case, I'd have to dig into my old textbooks to figure out what the reduction in flow would be with the valve wide open after I install some pressure valves before and after the ball valve. I'm not going to do this because I spoke with Yamaha and asked them if they knew what kind of tolerance there was with respect to reducing flow by adding a valve, and their answer was simple, "we don't know, we've never tested this, so don't do it". Obviously many have successfully done this on many models, but if you have a warranty, and your engine fails, this is an easy one for Yamaha to use to void your warranty.
That's my perspective.
I'm going with the radiator hose clamps.
Maybe not the easiest to clamp on in rough seas while laying between two hot engines, but that's what I'm comfortable with. And in the end, maybe I'll have some scars to use as a story to tell over a beer or two, or three, or four...
Just my 2 cents.

 

[buckbuck]

MrMoose, I agree with you about the restriction placed in the cooling line if a valve is installed. My personal experience dictates that I will not place anything that would reduce the flow. If I need to clamp a line to be towed I have a pair of vise grips with duct tape wrapped around the teeth of the jaw.

 

[MrMoose]

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.