Possible cooling system problems

[islandstyle57]

Thanks for this website, it has been a blessing for me in many ways.

Now with my questions that may have already been answered in earlier posts, yet in searching I have not found the answers.

I took my 2008 232 LTD in for annual maintenance at our local Yamaha 5 star dealership. When I called about picking it up, they tell me that I have an overheat problem on my port engine. Apparently, it is not showing up on the light on the tach, and it is not cutting my RPM’s back, not shutting the engine down. They want to replace the tach, pull the engine and remove the head in order to locate the obstruction that must exist in a cooling channel internal to the head. The estimate right now for the work is adding up, currently in the $1900.00 range.

I am not so sure that the engine needs to be removed from the boat, or that the head needs to come off, or that is a problem with the tach.

I am tempted to just pay for the annual Maintenance and the run some Salt Away through the engine for a week in 24 hour intervals and see if I can clear up any salt build up that may have accumulated in the cooling system.

Any advice from the jet boat community would be greatly appreciated.

Thanks again.

 

[Ilmmct]

I had a thermostat and tach go on my boat after 3 years of saltwater use. I am impressed you have gone 9 years without encountering these issues. Last year when the thermostat failed I was on the water and had to limp home at idle speeds. During this "event" a plastic exhaust resonator also got hot and deformed, which was caused heat to buildup (due to the blockage and heat not escaping properly).

The mechanically inclined members will weigh in soon, But pulling the engine seems excessive unless they have already inspected all the external cooling and exhaust systems/flow. I remember reading a thread by @buckbuck that included pictures and many details about the cooling systems on these boats ... hunt around for this post if you are going to attempt DIY measures.

 

[Ilmmct]

When I reference "mechanically inclined" members ... this is an example of some of their work and the video that should help on your DIY exploits:

https://jetboaters.net/threads/bad-thermosensor-intermittent-overheat.8032/

 

[islandstyle57]

I had a thermostat and tach go on my boat after 3 years of saltwater use. I am impressed you have gone 9 years without encountering these issues. Last year when the thermostat failed I was on the water and had to limp home at idle speeds. During this "event" a plastic exhaust resonator also got hot and deformed, which was caused heat to buildup (due to the blockage and heat not escaping properly).

The mechanically inclined members will weigh in soon, But pulling the engine seems excessive unless they have already inspected all the external cooling and exhaust systems/flow. I remember reading a thread by @buckbuck that included pictures and many details about the cooling systems on these boats ... hunt around for this post if you are going to attempt DIY measures.

Thanks for the reply Ilmmct, I appreciate it. I have already reviewed the video many times, great work on @buckbuck's part, it has really helped me understand the cooling system, that is why I am a little hesitant about my dealer's service departments diagnosis. They made no mention of suspecting any of the sensors or the thermostat...one of the first things out of the service writers mouth was pulling the engine. As for 9 years, I am the second owner and have no idea about the care or issues that the original owner may have had with the boat. I am going to the service department this afternoon for a complete walk through of the work required and I will probably just take it home.

 

[Ilmmct]

Good luck, that exhaust resonator was a red herring in my issues last summer. I escalated to YES (was under warranty) and the southeast regional Yamaha service lead tech, who helped my NC-based dealer diagnose the issue after the usual suspects (thermostat, tach) were replaced and not resolving the issue.

With some mechanical know-how and this forum, I believe you'll have the boat back faster and save yourself lots of money. If our boats share the same Tach (some parts cross-lookup work on your end), I have the replaced "bad Tach" the dealer pulled off my boat last summer. Not sure it is actually bad, so kept it as a back-up ... yours if you think it might help with diagnostics.

 

[islandstyle57]

Thanks again, I may take you up on the diagnostics help. First I need to get to the service department, I also might add that I know the owner of the dealership and I am on good terms with him and he is going to be there this afternoon to go through the walk through, so hopefully I will get better information from the service writer then.

 

[Scottintexas]

it's overheating but not indicating on the gauge or going into limp mode ? sorry but I don't believe it or wouldn't pay $1,900. for them to guess at it.

Do you have a YDS ? if not I would get one and run it yourself on the water and watch your engine temps to determine yourself what you see.

How mechanically brave are you? I would certainly believe you may have some salt/sand blockage somewhere in cooling port on the exhaust as we've seen that before or a thermostat especially on saltwater boats but just like buckbuck found out on his 08 it was only a fitting plastic fitting that didn't get all the leftover form cut out that caused his intermittent issue.

It could be a cooling port and the engine may have to be pulled and it's worth it to you to pay someone else but I would definitely diagnose it more myself before I raise my hand and open my wallet.

 

[scokill]

Obviously (maybe not if they are dishonest) they ran the engines to do some sort of determination. I would want to see how they diagnosed. If they ran on hose with some sort of temperature probe or hooked up to diagnostic port I would want to see if for myself with both engines....i.e., compare the temp on one engine to the other. This doesn't sound right to me moving from unknown overheat problem to pulling the engine and head just to have a look see on a suspected obstruction. If it does have an overheat problem and they replaced the sensor, replaced the thermostat, etc. and then come to that conclusion that sounds a little more reasonable but it still seems like they are on a fishing expedition when that should be the last resort.

Seems like to me that if you had a serious overheat issue and you've been running all this time that you would have fried a head by now.

 

[Zonie]

Definitely get or borrow someone's YDS and check it yourself. It will tell you every code that has been set including when. I don't know how the dealer would know it's overheating presently unless they took the boat out on the water. They might have just seen previous overheat codes that could be old or could have been temporary overheat issues from something you picked up in the water.

 

[islandstyle57]

it's overheating but not indicating on the gauge or going into limp mode ? sorry but I don't believe it or wouldn't pay $1,900. for them to guess at it.

Do you have a YDS ? if not I would get one and run it yourself on the water and watch your engine temps to determine yourself what you see.

How mechanically brave are you? I would certainly believe you may have some salt/sand blockage somewhere in cooling port on the exhaust as we've seen that before or a thermostat especially on saltwater boats but just like buckbuck found out on his 08 it was only a fitting plastic fitting that didn't get all the leftover form cut out that caused his intermittent issue.

It could be a cooling port and the engine may have to be pulled and it's worth it to you to pay someone else but I would definitely diagnose it more myself before I raise my hand and open my wallet.

it's overheating but not indicating on the gauge or going into limp mode ? sorry but I don't believe it or wouldn't pay $1,900. for them to guess at it.


Thanks for the reply, getting a YDS is on the priority list. Mechanically brave, I am no coward, but at this point in my life my time may be more valuable so paying someone else to do the dirty work is always in mind, but not $1900.00 and counting. If I cannot get a better feel at the dealer this afternoon I will be towing home and starting the process of elimination myself, or at least until the wife has had enough and wants to get back out on the water. Our vacation in the Keys is right around the corner and she is itching to go diving.

 

[islandstyle57]

Thanks for the reply, getting a YDS is on the priority list. Mechanically brave, I am no coward, but at this point in my life my time may be more valuable so paying someone else to do the dirty work is always in mind, but not $1900.00 and counting. If I cannot get a better feel at the dealer this afternoon I will be towing home and starting the process of elimination myself, or at least until the wife has had enough and wants to get back out on the water. Our vacation in the Keys is right around the corner and she is itching to go diving.

 

[islandstyle57]

Obviously (maybe not if they are dishonest) they ran the engines to do some sort of determination. I would want to see how they diagnosed. If they ran on hose with some sort of temperature probe or hooked up to diagnostic port I would want to see if for myself with both engines....i.e., compare the temp on one engine to the other. This doesn't sound right to me moving from unknown overheat problem to pulling the engine and head just to have a look see on a suspected obstruction. If it does have an overheat problem and they replaced the sensor, replaced the thermostat, etc. and then come to that conclusion that sounds a little more reasonable but it still seems like they are on a fishing expedition when that should be the last resort.

Seems like to me that if you had a serious overheat issue and you've been running all this time that you would have fried a head by now.

I agree, that is why I am meeting with them this afternoon and going over their process. They did tell me that they only saw the overheating when they measured it externally and only around the cathode by the number 4 cylinder.

 

[islandstyle57]

I met with the owner, 2 mechanics and the head of the service department.
The end result, I will be taking the boat home and working it myself.
Thanks for all your help and comments...anybody ever pull the heads off a MR-1 engine?
Thanks,
Greg aka, islandstyle57

 

[Scottintexas]

I've been thinking more on this, did they show you the cathode where they were taking the measurement? It could be a blocked passaged and increasing the heat in that area, whether that would cause a problem without triggering a sensor I don't know,

You could buy a infrared thermometer gun and check it yourself and against the other engine while out running.

here is a link to a YJB post about removing the head, it asked me to sign in so I don't know how good it is,
http://yamahajetboaters.com/forum/viewtopic.php?f=7&t=22265

or this from SBT
https://www.shopsbt.com/pdfs/yfx.pdf

do you have a shop manual? if not pm your email address and we can discuss it offline,

 

[islandstyle57]

I asked the mechanic the same question about the anodes as they were showing me photos of other engines they have recently worked on. His reply was no, he did not have to pull either one of them, he already new what the result would be due to the location of the 190 F high temp reading he was getting from his IR temp gun. He did add that corrosion (in my case salt) would build up on the anodes reducing the flow path. When they install new ones they cut them down in order to facilitate the flow of cooling water around the cylinder. That will be one of the first things I will do when I get my boat home. I also plan on a few flushes using the methods that CrankGypsy outlined in one of the forums, checking the thermostat, along with some runs using the IR gun to verify the temperatures before I replace tachs, sensors, or remove the head. PM'd my email, thanks!

 

[Ilmmct]

Good luck, hope this easier initial explorations get you on the water quickly.

 

[islandstyle57]

Thanks for the goodwill, I hope so too, back on the water and out of the doghouse. The wife wanted a pontoon boat with an outboard and I talked her into this one.

 

[Cobra Jet Steering LLC]

ok so have you read the temp with a remote thermometer? because Yamaha has a history of having defective heat sensors that put you in limp mode but the engine is not really hot so check the actual temperature if you have not done that.

 

[islandstyle57]

Thanks for taking the time to respond, I am purchasing a IR remote Temp gun today and will be flushing and reading temps tomorrow. The mechanic told me the highest reading he was getting was 190oF above the anode on I believe is cylinder 4. I am thinking about removing and plugging the cooling lines to and from the exhaust manifold and filling the engine block jackets with an Anti-salt solution such as Salt-Away or Salt-Terminator and letting it stand for 24 hours and then flush some more, all this after checking/replacing the anodes and the thermostat.
Any thoughts?

 

[Cobra Jet Steering LLC]

I believe you also said a tach was not working,, check all the wire connections behind the dash be sure they are clean and check the ground wire for a clean connection and especially for internal corrosion where the wire looks ok until you pull on it and you can stretch it meaning the wire inside the coating has turned to powder. Historically ground connections and pin connections are the first suspect with tach issues.
I would also advise you to remove your thermostat and place it in a small pan of water on the stove to heat it using a cooking thermometer to see the temperature of the water while you look to see when the thermostat opens. This will tell you if the thermostat is working.