increase cooling?

[cybuch]

We have been flyboarding for a few weeks now without issue tilL today. While I was flyboarding I had the motor report high temp and go into protect. We let it cool down and verified both pissers were peeing and didn't have any other trouble the rest of the day. I would like to increase the cooling capability, just in case. We run here for several hours at 5k to 9500 rpm. The other problem is our lakes aren't exactly cool here in AZ. Any thoughts on how?

 

[Julian]

First thing I'd do is check the intake strainers and make sure they aren't partially blocked with something.

 

[Speedling]

http://yamahajetboaters.com/forum/viewtopic.php?f=3&t=54133&hilit=cooling
buckbuck1 found that there can be a flashing casting issue in some of our boats' Y piece coming from the pump. Worth a look if you're going to do it full throttle all the time.
Not much you could do aftermarket.

 

[Bruce]

I wonder if you could add electric pumps with their own intakes to provide additional water for cooling? You could use the flush hoses to supply the water to the engines. You certainly would need a check valve in the line to avoid sending coolant out through the pump.

Running the extractor fans in the engine compartment should help a little.

 

[Murf'n'surf]

Bruce is onto something there. Your easiest and cheapest route may be to add blowers in the engine compartment that blow on the blocks and also get larger capacity bilge fans bringing in fresh air and exhausting the engine compartment air.

When one of our Volvo diesels are running too hot because they need their heat exchangers boiled out, I toss a fan on the motor and it keeps the temp down 10-15 degrees.

 

[Speedling]

Hmmmm, i wonder if the exhaust is getting sucked right back up, so it's extra warm? Perhaps moving around a little more will help?
It's still better by far than a closed loop system since you aren't moving. And it's not like you can put a cooler in line with the coolant because it goes straight from lake to engine and exhaust then out.

So, I think the air intake could be cooler then. Try opening the hatch while you do it?

 

[cybuch]

I agree, after the over heat I ran the factory bilge fans and it seemed to help. I think thats where I will start. Huge fans in the engine compartment, and I will post feedback. Has anyone installed temp sensors on the engine to get real time temps?

 

[Gym]

I think the combination of sitting static and running at high RPM is causing your issue. All good ideas and theories by above posters. Running the blower above certain RPM ranges, reusing previously exhausted hot water and additional engine air cooling. I think if you had minimal creep, possibly using the other engine you would keep a fresh supply of lake water to the intakes rather than regurgitating the exhausted water. Forcing water, by pump, into the cooling system may overwhelm the exhaust gasses ability to keep water out of the engine at lower RPM's and may not be advisable.

 

[Julian]

And don't forget to check your strainers and the aforementioned "Y" issue

 

[cybuch]

Strainers are a check as well as the "Y". And the flyboarder actually pulls the boat around the lake so it does move. It may have been a glitch, as we have been flyboaring for a few weeks without issue, but want to keep things cooler with the hot summers here. I will start with the blowers and go from there. Thanks all!!

 

[Gym]

I agree, after the over heat I ran the factory bilge fans and it seemed to help. I think thats where I will start. Huge fans in the engine compartment, and I will post feedback. Has anyone installed temp sensors on the engine to get real time temps?

@cybunch. As a test, or an inexpensive warning you could strap a digital gas grill meat thermometer to the exhaust manifold. Run the display outside of the engine compartment. Get a base reading of the manifold temp while running normally at high RPM. Then while you are flyboarding you can monitor the temp to see how high it goes. Note the temp on the thermometer if you get another over temp. That way you will know when you're approaching the danger zone and need to initiate additional cooling protocols like the bilge blower or creeping the boat. These grill thermometers also have a temp set feature that will alarm when reached so you could set it below the overheat temp to warn you.

 

[Gym]

Strainers are a check as well as the "Y". And the flyboarder actually pulls the boat around the lake so it does move. It may have been a glitch, as we have been flyboaring for a few weeks without issue, but want to keep things cooler with the hot summers here. I will start with the blowers and go from there. Thanks all!!

Does the flyboarder pull the boat forward or back?

 

[txav8r]

Does the flyboarder pull the boat forward or back?

Exactly what I was thinking...it is pulling the boat backward. And, our cooling comes from intake pressure flowing past the cooling intake screen. A boat static in the water is having to suck water into the cooling line. Not exactly a good setup. I tend to agree with Bruce, your going to have to increase the water flow. The additional air circulation may help, but an increase in water flow is what is causing your problem. It is very possible to overheat while running on a hose, due to decreased water, and increased rpm. So other than about 5000 rpm on a hose, you will be risking an overheat. Static in the water, you have good access to water, but nothing is pushing it into the engine/exhaust, so you need more flow.

 

[cybuch]

I defiantly have a ton of water flow, I am running dual impellers and the pissers are shooting water out like crazy! I am starting to think it was just a temporary clog. After the high temp we did some more flyboarding for about 2 hours without issue. I need to install a temp sensor so I can monitor it.

 

[Gym]

I defiantly have a ton of water flow, I am running dual impellers and the pissers are shooting water out like crazy! I am starting to think it was just a temporary clog. After the high temp we did some more flyboarding for about 2 hours without issue. I need to install a temp sensor so I can monitor it.

You may want to check your intake screens on the left side of the pump housings.

 

[buckbuck]

If you have a YDS you can track the two inputs the ECU uses to control the engine. They are the engine temp and the intake air temp. If you had strong flow then I am at a loss why you went to an over temp lock down of rpm. Below is a sample of info you can watch with the YDS.

 

[Julian]

I agree....most likely a cooling water pressure issue due to a blockage. If you are looking for a way to warn you in advance of an issue, you'd probably want a combination of cooling water pressure and RPM (but that would be involved). So simple temp alone would likely be the easiest.

 

[cybuch]

If you have a YDS you can track the two inputs the ECU uses to control the engine. They are the engine temp and the intake air temp. If you had strong flow then I am at a loss why you went to an over temp lock down of rpm. Below is a sample of info you can watch with the YDS.

Well, I have a strong flow now, don't know if it had a strong flow right when it went high temp. We shut it down right away and let it cool down. After that, I checked the flow and all was good. Since we are going to be doing this as a business, I am going to install a temp gauge and two flow meters on the cooling output so we can see when lose flow from the cockpit. Its hard to keep looking over the side and watch you flyer at the same time.

 

[Lspeedss]

@cybuch You know we have not considered cavitation or air infused water from the craft sitting pretty much static while your rider is on the board. That may contribute to the cooling issue.

 

[cybuch]

@cybuch You know we have not considered cavitation or air infused water from the craft sitting pretty much static while your rider is on the board. That may contribute to the cooling issue.

Hmmm, thats a thought. I did install dual impellers to combat that issue. Before the dual impellers, the boat would have cavitation, and no cooling issues. This was our second outing with the new impellers and first time for overheat.