How to detect overheat potential before it happens??

[Beachbummer]

So, After an awesome day on the water yesterday, I had my first direct experience with an overheat condition. One engine overheat light came on and it cut out like crazy for about 10 seconds before it shut down for good. I checked the clean out and there were some weeds stuck on the grate, which removed.

It turns out loading the boat just right, and with the tow valve closed on the overheated engine, with the trim tabs at just the right setting, with my Solas impellers... the boat will plane and will do about 16MPH on a single engine at 9200RPM or so (I bet it would have gone faster if I pushed the throttle some more, but I did not want to force the engine )...but Alas, the idiot driving did not clean the weeds from the running engine, so in another few minutes the running engine was out of service too due to the exact same problem. (Shame on me)

After clean out was checked, indeed it had weeds too!!! (Who would have thought) So, I cleaned those off and waited some more for the first engine to cool down and resume the trip. Eventually the second engine also cooled down enough to let me go and the universe was restored.

SO...

1)What's the deal here.... It would have helped greatly if I had been able to run the engine a little longer soon after to move cooling water into the engine once the obstruction was cleared. This seemed not possible as ignition was cut off until the computer determined I was worthy of trust again (Cooled down eventually). Is there a way to jump this? I know it sounds like a terrible idea, but I think once the deficiency is located and corrected it would cool much faster while running vs just sitting there air cooling... Any thoughts?

2)What crappy warning...how about a heads up? So, I need more gauges! What's the best spot to measure engine temp, and put a temp gauge on that? What about water temp on the water streams? The rear outlets seem to run much hotter than the front, at least at idle. Do I need to measure both to know what's going on? What if the flow stops? do I need some sort of water flow meter too?

I'm hoping I can put together some gauges to notice before it's an issue. I was already working on it before it happened as a project for the winter, but this has solidified my interest. Ideas welcome! I'd like the fewest possible gauges that will alert me the engine is not cooling enough, and that if I don't fix it, it will overheat, ideally as long as possible before the ECU puts me on a 30 minute time out.

Any thoughts?

 

[Beachbummer]

Nobody? I have an Arduino on order and some sensors... I expect to learn some things. I'll keep you updated but I welcome your ideas.

 

[2kwik4u]

Nobody? I have an Arduino on order and some sensors... I expect to learn some things. I'll keep you updated but I welcome your ideas.

I ran an electric fan in a project car off a contact temp sensor some time ago. It basically just wire tied to the thermostat housing, adn when it got to a certain point, would close a circuit. Used it with a 25amp relay to contorl the electric fan. Something like that wired to an LED would be a VERY basic setup.

Using the Arduino, you could run a couple thermistors taped/held onto various engine parts, and a simple digital readout to print the results. Would be a neat project, but would require some work to weatherproof it, and make it "marine compatible" for the long term.

I've thought several times lately of plumbing in a pressure sensor on the raw water feed from the jet pump. Get it good and cleaned out and take it for a run. Once you know what "normal" is, you can keep an eye on it to see if there are lowered pressures (and subsequent flows) to each engine.

I'm somewhat surprised that water temp isn't included in the factory instrumentation. The sensor is already in there somewhere, otherwise the overheat alarm wouldn't work. Perhaps you can just "tie" into that factory sensor and read the output with the Arduino?

 

[swatski]

Nobody? I have an Arduino on order and some sensors... I expect to learn some things. I'll keep you updated but I welcome your ideas.

different boat but @gmtech16450yz guy had a pressure or temp gauges installed on cooling water lines, I think.

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[Scottintexas]

sorry I was on my phone when I originally read this and didn't feel like typing on it to reply,
now that I'm on a key board,

I'm confused, your engine stopped working because of an overheat?
I thought it was supposed to go into limp mode with limited rpm, I mean great it shut itself off but I'd be concerned of what happened to the limp mode process,

I would think a temp sensor either after the thermostat or out of the thermostat indicator line, I don't think you care about pressure since if it doesn't have pressure it's not going to cool and run the temp up,

 

[2kwik4u]

different boat but @gmtech16450yz guy had a pressure or temp gauges installed on cooling water lines, I think.

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Any idea where he put them in the system?

I was considering putting pressure between the jet pump and the engine. There is a nice place for a fitting (and tow valve) right on the rear bulkhead on the engine compartment. Then putting temperature on the output line from the engine to the pisser.

As an aside, I hate the term "pisser", sounds crass......What else can we call that outlet fitting?

 

[MidnightRider]

I also had an overheat on Saturday due to weeds plugging up the grates. Could not get rid of the alarm and come out of limp mode by letting it just sit there with the batteries off. In fact even after loading it on one engine pulling it 45min home and putting it to bed - still had the alarm on startup. Wasn't til this morning that I could start it and the alarm was cleared. I was also wondering, is it best to let it sit and cool or what about after you see the engine peeing again if you ran it in limp mode with throttles "centered" and stepped up the rpm a bit with the no wake button - would that help cool it down better/faster?
One thing about these boats I've noticed, they really like to hold on to their engine codes/alarms - seems like it takes special type of vudu to get them cleared. I pretty successful clearing codes with the routine: key off -> wait 1 min -> batteries off -> wait 15-20 min -> batteries on -> start engines. But yesterday I didn't have any luck.

Edit: I'll also add that with how easy it is for these pumps to get clogged and shut down any cooling flow you'd think that Yamaha would put some visibility into the engine temps for the driver.

 

[swatski]

As an aside, I hate the term "pisser", sounds crass......What else can we call that outlet fitting?

People associated with the Boston area don't use that word at all.
They use pissuh instead.

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[MidnightRider]

Any idea where he put them in the system?

I was considering putting pressure between the jet pump and the engine. There is a nice place for a fitting (and tow valve) right on the rear bulkhead on the engine compartment. Then putting temperature on the output line from the engine to the pisser.

As an aside, I hate the term "pisser", sounds crass......What else can we call that outlet fitting?

Was always "pee hole" growing up. Probably not any less crass though.

 

[Matt Phillips]

I always thought the overheat alarm threw the engines into a limp mode and then shut them down until they cooled enough. As a general rule, if you have to remove the plugs to check for weeds and such, check them both. As I left the marina yesterday, the boat just didn't feel right...there was extra vibration in the system I could feel. As soon as I powered up, the starboard bounced against the rev limiter and I could head cavitation. She then settled down and ran similar to the port side. As soon as it was safe to do so, I moved out of the channel and pulled the plugs. the port Side had 1/2 handful of milfoil and the starboard only had some wrapped around the shaft in front of the impeller. However, when I reached down forward to the bottom of the hull to the intake I was able to get about 1.5 handfuls of milfoil out of that side. That's enough to likely disrupt the flow and possible cause an overheat. Thus I always check both tubes.

Does anyone know if -- after allowing the engines to cool down -- you can shut off the batteries for a few minutes then restart? Thus prompting the old fashioned reboot?

 

[Beachbummer]

Werid, mine limped (started to cut off hard, but shortly after shut down, maybe 10 seconds?). It would crank but not fire/catch. As soon as the overheat cleared, it started right up. How is the limp mode supposed to work? We were coming at 9200+ RPMs and I had been running for at least 40 minutes, maybe the last 5 went up from 8800 to 9200 (that was the last straw I'm sure) I suspect the heat soak as I slowed down probably put the engine over some other threshold? Anyway, crappy way to end, but I'm hoping it was a fluke and all is well. We did go out Saturday but we had company so I kept the speed reasonable, and we had no issues.

 

[swatski]

@Beachbummer I was also surprised your engines would just shut down, instead of going into a limp mode...

I was also wondering, is it best to let it sit and cool or what about after you see the engine peeing again if you ran it in limp mode with throttles "centered" and stepped up the rpm a bit with the no wake button - would that help cool it down better/faster?

I would think running them at high idle/no wake or low RPM about idle would cool much much faster. If the pissers are pissing (sorry @2kwik4u !) that rules out blockage or disconnect type of issues with cooling, I think.

One thing about these boats I've noticed, they really like to hold on to their engine codes/alarms - seems like it takes special type of vudu to get them cleared. I pretty successful clearing codes with the routine: key off -> wait 1 min -> batteries off -> wait 15-20 min -> batteries on -> start engines. But yesterday I didn't have any luck.

Yep.
My solution, if I'm in the middle of a lake and my cooling issue is fixed, would be to pull out the RIVA MaptunerX and reflash the ECU with backup file.

Edit: I'll also add that with how easy it is for these pumps to get clogged and shut down any cooling flow you'd think that Yamaha would put some visibility into the engine temps for the driver.

I'm not sure how helpful that would be honestly, given how fast the overheat condition escalates... I had a legit overheat last winter when one of my cooling lines froze (I did not blow the engines on the lift after previous outing), the overheat was on for that engine before I left the dock...

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[biffdotorg]

It must have been one of those weekends. As I too got my first overheat warning. MIne was actually shut off between tubing sessions and the port engine threw an overheat and would not stop with the steady beep.

I too would think that at idle circulating water would be the best way to cool it down. I was in the middle of the lake, so I was not even thinking weeds. We were tubing very aggressively with 800lbs of ballast in the locker and boat. It was such a nice wave for tubes, that we were putting on a beating with the teenagers.

I am going to pull my inlet screens and clean them up to be sure they are not blocked. My guess is they have not been cleaned since purchased from salt water over a year ago. But there was no lack of flow out the pissahs. And I monitor that on a regular basis. I'm over 50, it's a habit. HA!

 

[swatski]

Does anyone know if -- after allowing the engines to cool down -- you can shut off the batteries for a few minutes then restart? Thus prompting the old fashioned reboot?

I believe you need to actually disconnect the battery terminals for that, but I could be wrong.

One thing I've learned about Connext boats, need to wait min 20sec after ignition shutoff before turning the battery switches off. Otherwise the system throws a code that needs a dealer to clear.

 

[swatski]

It must have been one of those weekends. As I too got my first overheat warning. MIne was actually shut off between tubing sessions and the port engine threw an overheat and would not stop with the steady beep.

I too would think that at idle circulating water would be the best way to cool it down. I was in the middle of the lake, so I was not even thinking weeds. We were tubing very aggressively with 800lbs of ballast in the locker and boat. It was such a nice wave for tubes, that we were putting on a beating with the teenagers.

I am going to pull my inlet screens and clean them up to be sure they are not blocked. My guess is they have not been cleaned since purchased from salt water over a year ago. But there was no lack of flow out the pissahs. And I monitor that on a regular basis. I'm over 50, it's a habit. HA!

If turning aggressively the pumps can be starved of water and overheat, that's been reported.
More often in singles but who knows, maybe you were leaning too much to one side, lol.

Actually, yeah, joking aside, with ballast listing the boat you would be starving the opposite pump potentially.

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[biffdotorg]

Actually, yeah, joking aside, with ballast listing the boat you would be starving the opposite pump potentially.

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That may be possible, other than the pumps are literally at the lowest point of the hull. But in this case, the ballast was all centered.

All I know is it gave us a chance to take a swim break, leave the engine bay open, and drain what ballast I did have onboard. The wave size was bigger at 23mph, and the kids were loving it. I liked it, as the boat got on plane quickly, which surprised me.

 

[2kwik4u]

WOW, the wee-hole discussion really took a turn there. Fun Times. I'll keep thinking of an alternative.

I'm certain that running the engine at high idle would bring the temps down significantly faster than letting them sit. I've had my engine be too hot to touch after a few hour tow home. Adding just a little bit of circulation would help that situation. Likewise running the blower will help circulate some (not much but some) air through the engine bay. I found this to help with Vapor Lock issues caused by high engine temps on previous boats.

Once it's shut down for an overtemp alarm will it allow a restart at all, or do you have to clear the code first?

 

[Scottintexas]

it's a "indicator flow line"

@buckbuck am I making this up or did you determine the engine actually cools better at higher rpm with more water flowing ?

 

[thefastz]

I had the same thought recently, wanted to have a better idea of when the jets are clogged and I get tried of having to walk over to the side of the boat while running to ensure it is peeing out. The theory is, I am going to add 2 water pressure sensors (that are NMEA 2000 compatible) to the intake lines so that I can have the pressure data in my GPS. I really did not want to drill more gauge holes in the dash so this was a good alternative. I hope to tackle the install this week sometime, just received the NMEA 2000 backbone today and already have the sensors.

These are the sensors I picked up BTW

Search results for: 'low000 11523 001 navico pressure sensor nmea 2000'

www.hodgesmarine.com

 

[buckbuck]

I am just an ordinary guy who did some testing and found this

https://jetboaters.net/threads/cooling-water-pressures.3202/

After running hard like we did this weekend (daughter had to show ever one how to spin a boat at 10,000 rpm) we run them at around 7000 rpm for a minute. Years ago when I was having issues I did a lot of investigating while the YDS was connected. Going to idle, or worse, turning off the engines only caused the temperature to rise. This information pertains to the MR-1 engine but I would think the 1.8's are similar.
@Beachbummer I have never experienced a total shut down and lock out. Just a limp mode that limited rpm after temps as high as 244 degrees.