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

[Skysurfer2010]

Would this mod allow me to close off the value - like in tow mode. Then connect to a fresh water hose and flush the motor with fresh water? I ask this because I rent a house from time to time in Flordia without a lift. At the end of the day in salt water I would like to flush motors with fresh water. Interested in any feedback. Thanks

Yes, however do not follow the directions in this thread of where it says to place the shutoff valve. If you do it how the OP says you will not be able to flush your engine with it closed. You need to put it on the opposite side of the y so it doesn't close off your flush line (red hose). Place it behind the Y between the Y and the transom.

 

[xoomer]

Yes, however do not follow the directions in this thread of where it says to place the shutoff valve. If you do it how the OP says you will not be able to flush your engine with it closed. You need to put it on the opposite side of the y so it doesn't close off your flush line (red hose). Place it behind the Y between the Y and the transom.

That's right. It's a bit confusing since there are two issues here--where do you cut the hose, and where do you place the valve. It doesn't matter if the valve is in the engine compartment or under the clean out tray--as long as the hose is cut in the right place. In order to flush the engine the valve must be placed before the back of the "Y" where two hoses are connected. If the valve is in front of the "Y" where one hose goes to the engine, then you can use it for towing purposes but not for flushing.

In my case, I put the valve in the engine compartment but still managed to place it between the intake hose and the back of the "Y" by adding an extension to the intake hose.

 

[Scottintexas]

@xoomer thanks, that's a good diagram

 

[Geoff Cooper]

I looked at all aspects before fitting mine and the reason i chose to fit them under the rear tray was this

1) When i return to the marina it's easy access when i flush the engines while the Boat is still in the water
2) While checking for any debris inside the jets i can do the valves at the same time as they can be easily seen through the inspection holes
3) I didn't want to be laying over hot engines trying to locate shut off valves when i returned to the Marina before flushing sometimes it's dark when i get back.
4) I just undo the 2 covers and there they are easy and convenient to get to, If you have passengers they don't have to keep moving around to let you open the engine cover and you don't want kids roaming around Marinas while you find valves, Passengers can just stay put while you flush they don't need to move from the cabin area.

 

[xoomer]

Just for clarification, my tow valves are placed at the front of the engine so I don't have to reach over the engine to turn them on and off.

Once I arrive back at the marina I like to get all the passengers off since I want to do my shut-down, clean-up, and flushing without distractions. Just the flushing takes 10-15 minutes to get the hose ready and do the flushing on each engine and most people aren't interested in waiting on board while I do this and my other chores.

Overall, I don't think it really matters where the tow valves go as long as they are easy to reach and installed correctly.

 

[MOA_Chaser]

@xoomer ... I would like to install my valves similar to yours. There isn't very much hose before the Y fitting and I was thinking about extending it and looping it somehow. Who did you use as a source for the extended hose to loop around the engines? Do you know offhand what you bought and the lengths?

 

[xoomer]

@MOA_Chaser I bought a 5/8" automobile heater hose on Amazon. I think each engine required around 8' each--you might find this in an auto supply, and in shorter lengths, than on Amazon. Also, I used two 5/8" brass barbs to connect the new hoses to the intake hoses.

I had a lot of trouble reaching the clips holding the original hoses on but finally managed to get them off. On the port engine, since there wasn't much hose sticking through the bulkhead, I opened the clean out tray and pulled the intake hose back through the bulkhead--once it was disconnected from the "Y"--and was then able to install the brass barb much easier there. Then I fed the entire new hose back through the bulkhead. I don't think I was able to do the same thing on the starboard side since it was too hard to get to the intake hose.

I installed the tow valves after connecting the new hose but it might be better to install them before you connect the new hoses up--I suppose it depends on your configuration.

Make sure the new clamps you use to secure the hoses are large enough so that you will be able to do it easily--mine were too short and took a long time just to get them connected.

It's really not too difficult to install the tow valves except for removing those *$)($&# clamps--they are at the back of the engines and hard to get to on my boat.

 

[MOA_Chaser]

Yeah I already disconnected the port side Y fitting at the end of the season trying to figure out how I was going to do it... I remember it wasn't fun!

Those Island Racing valves look nice... but is that $25 a piece?? That's a lot of coin for a simple valve. I have the 3/4" stainless ball valves that I got last year that I could use for it, but I've been wondering exactly how much pressure goes through these lines and if barbed, all-in-one plastic ones would work.

 

[xoomer]

Yes, they are $25 each--I wanted a valve that was specifically made for this purpose so I decided to pay the price. Overall, I suppose I paid around $100 for the valves, hose, clamps and barbs. Not sure about the pressure or the use of plastic barbs or different valves.

 

[xoomer]

This can be confusing so here is a better diagram of my installation:

 

[txav8r]

I'm no expert here guys, but it looks like Yamaha has gone to great lengths, to keep the length of the cooling loop to a minimum length, pun intended. Water can only be forced so far under the same pressure, every corner and foot reduce it. I get the need to flush your engines in saltwater and admire your ingenuity to make that easier. But I wonder if adding all that footage will decrease your normal cooling capability. Again, I am no expert and this is just my thinking.

 

[xoomer]

I'm no expert here guys, but it looks like Yamaha has gone to great lengths, to keep the length of the cooling loop to a minimum length, pun intended. Water can only be forced so far under the same pressure, every corner and foot reduce it. I get the need to flush your engines in saltwater and admire your ingenuity to make that easier. But I wonder if adding all that footage will decrease your normal cooling capability. Again, I am no expert and this is just my thinking.

I don't think that is a problem. When I flush the engines with the tow valves shut I get a strong stream of water coming out of the "pee" holes. I would assume that if it were not cooling properly that the overheating warning would have come on by now.

 

[Geoff Cooper]

I don't think that is a problem. When I flush the engines with the tow valves shut I get a strong stream of water coming out of the "pee" holes. I would assume that if it were not cooling properly that the overheating warning would have come on by now.

This was one of the reasons i fitted mine under the rear tray directly where they are needed, If i remember by my calculations it took 1 bar to move water 18 ft so if for example you are adding 6ft to each engine that's nearly 1/2 a bar each and could affect the cooling to a degree, under the rear tray your not adding any extra length only a couple of inches for the valve, I fitted a clear pipe to see what power the water came through the valve and it was quite powerful i was surprised.

 

[txav8r]

@xoomer , it may be of no consequence today, but any trash along the way, it is just a longer distance and more opportunity for it to cause a problem down the road IMO...and less pressure to move any trash that you do ingest, such as sand/dirt. Several members have found sand in there engines passages reducing cooling and causing cooling issues after the fact, and had to tear them down to repair. I am not saying that will happen, but...

 

[xoomer]

@txav8r I think it would be better not to install any additional hoses or valves anywhere in the boat but I had to weigh the possibility of creating a problem with the installation of the tow valves vs. a potential problem from the guys who do the flushing where I keep my boat not doing the flushing properly. I can't wait around for them to take my boat out of the water every time for me to do the flushing since it may take an hour or longer for them to get to my boat.

My first thought was to put the valves in the back but that was impossible for me to do without a lot of work that I wasn't interested in doing--so I chose to put them in the front. So far, after more than a year, I haven't encountered any problems and hopefully it will remain that way.

 

[txav8r]

It will probably be just fine. Everything in boats, airplanes, even cars and trucks, is a compromise.

 

[MOA_Chaser]

Or it could be that they are minimizing the raw materials in manufacturing to put profit in their pockets. Saving $10 worth of raw material cost and selling 50,000 watercraft is a "profit" of a half a million dollars right there.

THAT BEING SAID, with a longer length of hose (and possibly even without lengthening the hose) it would probably be a good idea to install a debris trap or filter close to the inlet to keep the line clear and avoid getting debris in the engine.

 

[txav8r]

Or it could be that they are minimizing the raw materials in manufacturing to put profit in their pockets. Saving $10 worth of raw material cost and selling 50,000 watercraft is a "profit" of a half a million dollars right there.

THAT BEING SAID, with a longer length of hose (and possibly even without lengthening the hose) it would probably be a good idea to install a debris trap or filter close to the inlet to keep the line clear and avoid getting debris in the engine.

I think that has been attempted and it will restrict flow. The intake has a screen, if you want to call it that, already installed. But it is more like a "grate". A screen won't let enough water through and it will overheat. That is what worries me about the length of the added section.

 

[tdonoughue]

While I agree with @txav8r , the point is well-taken that if a boat is on salt all the time, constant flushing probably does the engine more good than the extra length does bad. Myself, I boat only on fresh water and store it on the trailer. Would not make sense given my usage. But for a salt water boater, this could be a very reasonable compromise, IMHO.

 

[xoomer]

If for any reason you wanted the tow valves in the engine compartment but were worried about the additional length of hose, it would be easy just to use a much shorter hose and place the valves in-between the two engines, just forward of the bulkhead--this way you would only be adding a foot or two of hose. The only issue would be that they wouldn't be as easy to reach.