Really weird issue need help. Engines overheating randomly Yamaha/Dealer says it’s not happening

[NewBoater]

Thanks for the input fellas. I definitely don’t expect him to clean it again in a few years if it happens again. I will start using salt away going forward so hoping it never happens again.

 

[CrankyGypsy]

I'm seeing this really late into the discussion - kinda skimmed through it.

I fully agree with everything that @Scottintexas has been recommending. My only concern is that it seems both engines are overheating simultaneously, correct? Is there some newer safety feature that throws both engines into limp mode if one goes? Aside from that...

As Scott mentioned, how thorough do you think the shop is really going to be? Ask them. Unless they soak these pieces in sulfamic acid (which is not mentioned anywhere in the manual, btw) or replace every part (including the block), there's a very good chance you'll pay for an incomplete job. And then you still may have to deal with a crazy sensor issue, though I have a link in the flush write-up to assist with sorting that out. We have all learned this: no one cares more about your boat than yourself.

This was brought up, too: yes, sand will also be flushed out with my method. The acid breaks up the calcium binder, plus the larger sand particles are pushed out easier by the increased flow current. My belief is the film of salt, calcium, and sand act like a ceramic thermal insulator ...it needs to go.

In regards to your mechanical skills, we all had to start somewhere. That first project is the one that gives you confidence for the next. I tried to write the flush instructions with the beginner in mind (the instructions on my site are even easier to follow) and you'll notice there aren't any fancy/expensive tool requirements. Your engines are a bit different, but we are here to help you through that aspect.* Once you get the supplies together and the engines assembled (and running), you will be able to flush them well within a weekend's time, no matter your level of expertise.

* That is one of the shortcomings I have found in owning a SeaDoo: the quality/thoroughness of info/help just isn't at the level of support I had gotten used to here - info is very commonly scattered, vague, accidentally incorrect, or incomplete.

I'll admit I have my own selfish reason for you doing the flush, though: I want to see someone else's results using my method. If you've got the time and patience, I say give it a shot.

 

[WREKS]

Thanks for the input fellas. I definitely don’t expect him to clean it again in a few years if it happens again. I will start using salt away going forward so hoping it never happens again.

Is your boat up and running again without any overheats? Reason I ask is that I started a few threads regarding plugged cylinder heads and cylinder block water jackets. I have had these problems shortly after acquiring my boat new in 2007. The marketing videos made it seem like beaching the boat was the way to go. I do not think Yamaha disclosed the problems that can develop when sediment is forced into the cooling system, which is a very common occurrence when finding ourselves in shallow water. I have had overheat problems for 12 years. I finally built my own engine hoist and pulled both engines. I do not believe flushing could remove all the hardened deposits I found in the head and block.

 

[swatski]

I do not think Yamaha disclosed the problems that can develop when sediment is forced into the cooling system, which is a very common occurrence when finding ourselves in shallow water.

Is white/grey material deposited inside the cooling passages not aluminum oxide?

Do you boat in salt or fresh water? If fresh, do you know if the pH is neutral? or could it be acidic, or alkaline?

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[4x15mph]

Just reading this and wondering whether anyone installs water strainers to filter out sediment.... I had these in my boat and found a lot of sediment although my boat didn’t have screens on the intake.

 

[WREKS]

Thank you for responding swatski and 4x14mph. It is a sand colored, very fine, clumps when wet and when allowed to dry out, sets up not unlike mortar if allowed to dry over an extended period of time. The grey in the collection is sediment that was removed after soaking cylinder block water jackets in distilled household vinegar. The blackish pieces are head gasket coating. BTW, I boat in salt water.

 

[4x15mph]

@WREKS, that is a mess and I think this will clear up your issues with cooling so long as the exhaust isn't also clogged up. Was it easy to remove the head and take that out of the engine bay or was there a lot that had to be detached?

I read a lot of this thread but to recap, given you boat in salt water, do you flush with anything other than water?

 

[WREKS]

@WREKS, that is a mess and I think this will clear up your issues with cooling so long as the exhaust isn't also clogged up. Was it easy to remove the head and take that out of the engine bay or was there a lot that had to be detached?

I read a lot of this thread but to recap, given you boat in salt water, do you flush with anything other than water?

On both of my engines, the worst place for the buildup has been in the cylinder block water jackets. The closer it is to cylinder [HASH=108]#1,[/HASH] the worse it is. The cooling water intake for the water jackets is located on the opposite end at the bottom of cylinder #4.

Regarding flushing: both motors have always been flushed except for one time when I sucked up a tie-off line.

Regarding work involved: Much. I had to remove the engines in order to work on them. I was able to fabricate a gantry crane suitable for doing this.

 

[haknslash]

Regarding flushing: both motors have always been flushed except for one time when I sucked up a tie-off line.

Are you flushing with just water though? It sure looks like it. You need to use something that will breakdown the salt crystals. Salt Away, Salt Terminator, etc. Just using water isn't enough.

 

[swatski]

On both of my engines, the worst place for the buildup has been in the cylinder block water jackets. The closer it is to cylinder [HASH=108]#1,[/HASH] the worse it is. The cooling water intake for the water jackets is located on the opposite end at the bottom of cylinder #4.

Regarding flushing: both motors have always been flushed except for one time when I sucked up a tie-off line.

Regarding work involved: Much. I had to remove the engines in order to work on them. I was able to fabricate a gantry crane suitable for doing this.

So, in salt water the issue with Yamaha jet boat engines is cooling water not draining at the end of the day, as it would in an outboard motor.

Without some serious salt and corrosion prevention program such as flushing with salt removal/ corrosion prevention agents or strategically placing intake valves that would prevent flush port water from escaping through pump (force flush port water into engine/exhaust cooling passages) - corrosion will quickly eat the aluminum in the passages.

After that I think it's hard to tell a "cause-effect" here. Is trapping of sand/sediment happening because of aluminum surface pitting in cooling passages and accumulation of aluminum oxide crystals?

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[WREKS]

Are you flushing with just water though? It sure looks like it. You need to use something that will breakdown the salt crystals. Salt Away, Salt Terminator, etc. Just using water isn't enough.

Thanks haknslash. Very early on I used water to flush the engines. Then I switched to Salt Away There is really nothing crystal about this stuff. It pulverizes to a power between my thumb and forefinger. I went so far as to taste some. I do not think there is any salt there. I would liken it more to fine sand. In places in the water jackets it got packed pretty hard, especially by cylinders #1 and [HASH=15]#2,[/HASH] the furthest from cylinder #4 where the cooling water enters through a peep hole. My advice to fellow members is try not to suck up anything off the bottom and before taking the boat out of the water run it at WOT to hopefully wash out any salt/sediment that may be starting to collect in the water jackets.

 

[WREKS]

So, in salt water the issue with Yamaha jet boat engines is cooling water not draining at the end of the day, as it would in an outboard motor.

Without some serious salt and corrosion prevention program such as flushing with salt removal/ corrosion prevention agents or strategically placing intake valves that would prevent flush port water from escaping through pump (force flush port water into engine/exhaust cooling passages) - corrosion will quickly eat the aluminum in the passages.

After that I think it's hard to tell a "cause-effect" here. Is trapping of sand/sediment happening because of aluminum surface pitting in cooling passages and accumulation of aluminum oxide crystals?

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swatski, Would you , please, elaborate on your statement,"...strategically placing intake valves that would prevent flush port water from escaping through pump (force flush port water into engine/exhaust cooling passages) - …?" I am not sure what the "intake valves" are that you are referring to.

 

[swatski]

swatski, Would you , please, elaborate on your statement,"...strategically placing intake valves that would prevent flush port water from escaping through pump (force flush port water into engine/exhaust cooling passages) - …?" I am not sure what the "intake valves" are that you are referring to.

One option is to install basically tow valves in the bilge under swim platform, permits very good flushing in and out of water as @Gym does:

I boat exclusively in salt water. We leave it in often for 2 to 3 days a week. Your biggest concern is flushing the engines with Salt Away or similar product. I have tow valves installed which allows me to flush with fresh water and Salt Away while sitting in salt water. You can easily get a couple of clamps to clamp off your water intake, flush your engines after each use, then remove your clamps. Your boat will suffer no I'll effects wit a week or so in the salternative as lon as your flush after eachieve use. Just clean the boat well after it comes out. Also rinse your trailer and brakes well after the launch and retrieve. Is your trailer galvanized or painted?

 

[WREKS]

One option is to install basically tow valves in the bilge under swim platform, permits very good flushing in and out of water as @Gym does:

I get it. Thanks!

 

[NewBoater]

Knock on some serious wood fellas I have been problem free all summer since I got it back from the dealer. I paid them $1,300 ish for their full diagnosis of what was wrong (taking off exhaust and reinstall also) and to do a partial cleaning of the big salt stuff that they could get to. I did not do the over $4000 full overhaul salt removal they wanted to get every single piece of salt out.

Also I have been super religious about using salt away after every single trip directly when we finish once I put it back in the lift. I also did the full salt away overheating treatment that it says to do on the back of the salt away bottle if you have had overheating problems. . I think it was 5 straight days I ran salt away around lunch time once a day. I did this full treatment for a week before we started using the boat again. I wanted to get as much salt as I could out myself before we started using it again.

We have used the boat hard for the last two months many trips an hour each way and tons of water activities tubing, wake boarding etc. . Not a single overheat. Again knock on some serious wood. I’m a believer in salt away now and will continue to use it with any jet boat I ever own. Really wish I would have used it from the beginning for the first couple of years. Very cheap insurance.

 

[swatski]

Knock on some serious wood fellas I have been problem free all summer since I got it back from the dealer. I paid them $1,300 ish for their full diagnosis of what was wrong (taking off exhaust and reinstall also) and to do a partial cleaning of the big salt stuff that they could get to. I did not do the over $4000 full overhaul salt removal they wanted to get every single piece of salt out.

Also I have been super religious about using salt away after every single trip directly when we finish once I put it back in the lift. I also did the full salt away overheating treatment that it says to do on the back of the salt away bottle if you have had overheating problems. . I think it was 5 straight days I ran salt away around lunch time once a day. I did this full treatment for a week before we started using the boat again. I wanted to get as much salt as I could out myself before we started using it again.

We have used the boat hard for the last two months many trips an hour each way and tons of water activities tubing, wake boarding etc. . Not a single overheat. Again knock on some serious wood. I’m a believer in salt away now and will continue to use it with any jet boat I ever own. Really wish I would have used it from the beginning for the first couple of years. Very cheap insurance.

The salt-away active ingredient is sulfamic acid or sodium nitrite, both used in food production and readily available.
I would always use their original, at $30(?) a gallon there is no excuse, but a home brew would be easy to put together, too.

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[WREKS]

I get it. Thanks!

Thanks for that update, NewBoater. Keep up the good work. I know you will.

 

[FLJetBoater]

I haven't read this entire thread going back to August 2018 so I apologize if I'm asking questions answered. Do you boat in salt water? If so do you flush religiously after each use. If you don't you may have salt buildup in the cooling passages. Does this overheat condition happen to both engines? Do you beach your boat? One of our members found fine sand blocking some cooling passages on the exhaust side causing his overheat.

To determine if this is a real overheat you can take the temp of the pee water during a normal run. If you get an overheat warning take the temp of the pee water again. If the water temp is significantly higher it's an actual overheat and not the sensors.

I’m having a similar overhead situation I’m trying to diagnose. But, could you explain the logic here? If the water isn’t getting into the engine to cool it, why would it feel significantly hotter than a normal run? I would expect the water to be significantly colder then before since it’s just going from lake/river/etc straight out the pisser. If it was a sensor and the engine was actually being cooled I would expect it to have the same temp as before. Am I missing something?

 

[Cobra Jet Steering LLC]

What I do is take external readings of the engine the exhaust manifold and the muffler using a non contact gun , there are several heat sensors and yamaha had a bad reputation for those going bad , have not heard of it lately but you could have a sensor heck my bad sensor put the ski in limp mode and the alarm would sound intermittently but it was never hot in reality. The water coming out of the side of the boat is coming from the engine so it would be hot if the engine was overheating or it may not if it is the exhaust sensor messing up or the exhaust not cooling properly.

 

[FLJetBoater]

What I do is take external readings of the engine the exhaust manifold and the muffler using a non contact gun , there are several heat sensors and yamaha had a bad reputation for those going bad , have not heard of it lately but you could have a sensor heck my bad sensor put the ski in limp mode and the alarm would sound intermittently but it was never hot in reality. The water coming out of the side of the boat is coming from the engine so it would be hot if the engine was overheating or it may not if it is the exhaust sensor messing up or the exhaust not cooling properly.

Is there a cooling video for the 1.8s? Are you saying that if there is a strong stream coming from the pisser that water is coming from the cooling passages? In my case there is a strong stream, so the engine couldn’t possibly be overheating?
I thought I read somewhere that water from the pissers wasn’t a solid indication that water was actually entering the cooling passages.