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

[NewBoater]

If the thermostat had salt then it's definitely possible
Look at this thread

https://jetboaters.net/threads/bad-...t-overheat.8032/[HASH=153]#post[/HASH]-138920

So his problem was a bad heat sensor? Are you thinking that could be my problem?

 

[njmr2fan]

I've experienced this several times in our 190 and it was always when tubing. I noticed that when tubing, we were tossing around the kids on the tube and switching them out after a few minutes. This meant shutting off a heat soaked engine, letting the kids on and off and then going back to crazy boating. As @swatski mentioned, the engines don't get enough cooling water through them. Our solution was to slow down after a session and give the engines an extra minute to flush some water through them.

 

[Scottintexas]

So his problem was a bad heat sensor? Are you thinking that could be my problem?

Honestly I don't know, I would think the dealership has already checked all the electronics before they start removing pieces searching for "corrosion". I wouldn't doubt even my manifolds that don't see salt water have some sediment build up, I'd want assurance if they remove your manifold, clean the ports and it doesn't fix the problem they are going to credit you that money,
You can see what they are talking about here

I had seen a you tube showing instructions how to clean but can't find it at the moment,


This is crankygypsy's flush/restoration method,

https://jetboaters.net/threads/closed-loop-flush-of-mr-1-with-marine-descaler.8443/

I know you said your not very mechanical, maybe you could post a "need help in VA" thread and maybe there is a member nearby that could help,

time is money but also trusting the mechanic and knowing he's not burning your money also comes into the equation,

If it was me I'd bring the boat home and try Cranky's flush, but your time/money may justify a different path,


.

 

[swatski]

I've experienced this several times in our 190 and it was always when tubing. I noticed that when tubing, we were tossing around the kids on the tube and switching them out after a few minutes. This meant shutting off a heat soaked engine, letting the kids on and off and then going back to crazy boating. As @swatski mentioned, the engines don't get enough cooling water through them. Our solution was to slow down after a session and give the engines an extra minute to flush some water through them.

I agree. But this looks to be possibly an internal passages corrosion issue, too.

—

 

[Spooling]

Our solution was to slow down after a session and give the engines an extra minute to flush some water through them.

That's what we've always done at well. It's crazy to run an engine full out then immediately shut it down. I always slow it down, above idle, to let it cool off before shutting down. I

 

[NewBoater]

Called Yamaha they said the only thing they would cover is faulty parts on their end but they think it’s build up like the dealership (which they won’t cover). The boatel is going to pull the exhaust $350 ish and see how bad it is and how much it would take and labor to clean the build ups from everywhere it is. Saga continues

Even if they get this fixed and all cleaned is this something I’m going to have to deal with every 2 years of boating?

 

[haknslash]

Even if they get this fixed and all cleaned is this something I’m going to have to deal with every 2 years of boating?

Not likely if you use Salt Away, Salt Terminator, vinegar, anything’s other than just tap water to aid in flushing. Normal tap water isn’t going to break down salt crystals effectively and I could see corrosion being any issue long term. If you haven’t used Salt Away before it basically dissolves the salt crystals. I know the manual says to simply use water but if you Salt boat then you know just rinsing water on your hull does not remove the hard crusty feel of the salt, so imagine inside your engine’s tiny water cooling passages and jackets....

 

[njmr2fan]

Not likely if you use Salt Away, Salt Terminator, vinegar, anything’s other than just tap water to aid in flushing. Normal tap water isn’t going to break down salt crystals effectively and I could see corrosion being any issue long term. If you haven’t used Salt Away before it basically dissolves the salt crystals. I know the manual says to simply use water but if you Salt boat then you know just rinsing water on your hull does not remove the hard crusty feel of the salt, so imagine inside your engine’s tiny water cooling passages and jackets....

I flush out our fresh water lake water using dawn dish detergent and a mixing valve attachment.

 

[Cobra Jet Steering LLC]

I had a bad heat sensor years ago on a supercharged Yamaha it was by the intercooler and it would set off the limp mode etc. for no reason even if the engine just started a few seconds prior for the first time of the day They found the bad sensor and fixed it, I have also heard of defective loose baffles in the muffler that blocked the passage of exhaust and water causing the sensor to trigger and put it in limp mode. When I had my issue I used a non contact thermometer to check various areas of the engine and never found any hot spots so I pretty well knew it was a sensor something Yamaha had issues with in the past .

 

[djetok]

Someone earlier in the thread suggested limeaway @Gym did. Would limeaway take the salt out ? Sounds like a good guess. Has it been done before?

 

[Gym]

Someone earlier in the thread suggested limeaway @Gym did. Would limeaway take the salt out ? Sounds like a good guess. Has it been done before?

Yes @djetok I have used limeaway. I run it straight with no water. Let it sit for 5 or 10 minutes then I flush with water. If I see the water come out pretty dirty I do it again. I've only done this process twice over the 7 years I've had the boat.

 

[NewBoater]

Fellas, here are the pictures I was sent and I was told there was salt buildup in both motors. They are working up an estimate to fix it. Sounds expensive, does this look bad to you guys? Should I expect this to fix my overheating problem? Thanks

Motor 1 pics

 

[NewBoater]

Motor 2 pics

 

[Julian]

Clearly that is going to cause you cooling issues. Motor 1 looks way worse than 2, but they are both not good. Will this fix the issue...most likely, unless there is something else wrong too.

 

[Beachbummer]

Evaluate their estimate and what they plan to do. One looked really plugged up.. If there is no flow, the flushes alone can't help, so that's a vote for them to address. Wait for the estimate.

 

[Scottintexas]

Well that could definitely be the issue, I'd ask them what their procedure is going to be to clean it, of course that build up is probably way up inside also so just hitting the visible areas with a drill/pipe cleaner will help but if I'm paying somebody I'd want it done right and not "it ought to work" You can google you tube for video of somebody else doing this exact process,

You had asked earlier if this was going to be a common occurrence for you, I think it will be if you continue your current procedures,
Either you have very tainted water, aren't flushing enough, the salt away really is that important, a mix of all the above,

If you don't start using salt away or some additive to your flush I would definitely consider Cranky's closed loop flush at least once or twice a year to help keep it clear (or clearer)

 

[Scottintexas]

You should also tell them to look at the exhaust manifold passages also,

 

[Scottintexas]

This was a cooling passage issue from YJB a long time ago,

Yamaha Jet Boaters • View topic - Replaced Exhaust Hose - Boat still Overheating. Waterlock??

.

 

[Scottintexas]

for future reference this is a good video showing water flowing, still looking for the actual cleaning video,

 

[NewBoater]

Thanks so much guys for taking the time to reply and all of your help so far. Waiting on the estimate.