Engine Overheating

[remo7e]

I went to pick up my boat (Yamaha 30 '84)from the marina after having a knot meter replaced. I motored about 10 minutes and the engine quit- no alarms, no red lights. I opened the engine compartment and black smoke billowed out. Sailed it back to the marina and the mechanic took a look and said that he thought it was a bad thermostat. I showed him that no water was coming out of the port, but that exhaust was.

Several hours later, they called my home and told me that the thermostat was fine, but that the head gasket has failed. The black smoke was due to them not properly clamping down a hose. Why would the head gasket cause the boat to not draw water? They want $2000 to replace the head gasket, which seems a bit high. How hard is this to DIY? Any help?

 

[Barnacle Bill]

Head gasket problem

Most likely the engine over heated and then the head gasket problem was a result of the overheating. If your engine overheated a great deal (very hot), it is possible that the head became warped from the excessive heat, which then lost the seal at the gasket. When this happens usually water passes through from the water jacket to the cylinders which results in white smoke (steam). If your head or any other part of your engine is discolored, that is a good indication that you really overheated it a great deal.
You still have to determine the reason for the overheating. Some things to rule out are:
1. Was engine water intake seacock closed?
2. Is there blockage in the water intake hose?
3. Is the water pump impeller bad?
4. Is the water pump bad?
5. Is there antifreeze in the closed cooling system? Applicable only if you have a closed system, of course.
6. Have you or anyone done any recent fresh water hot water heater work, installed a new one, etc. where there is a heat exchanger in the system which might not have been properly bled?
7. Are there any broken or damaged hoses in the fresh water intake cooling system?
8. Is there any blockage in any of the passages of the cooling system?
If the head is warped due to excessive heat, you need to mill the head to proper specs or replace it along with the head gasket. If you replace the head gasket, you will still have a problem if the head is warped. So, determine that your head is true.
Make sure the repair faciity knows what they are doing. So far there are too many unanswered questions.

 

[remo7e]

Re: Head gasket problem

Thank you! I will bring this to their attention today.

 

[remo7e]

Re: Head gasket problem

[FONT=メイリオ]This is what the marina is telling me. Does this sound right? [/FONT]
[FONT=メイリオ][/FONT]
[FONT=メイリオ][/FONT]
[FONT=メイリオ]He estimate the cost of replace Head Gasket is $2000 and takes two to three weeks at longest ( maybe two weeks?) since he is in busy now.[/FONT]
[FONT=メイリオ]Need to hoist the engine for replacement work, it's a lot of work.[/FONT]
[FONT=メイリオ][/FONT]
[FONT=メイリオ]The broken head gasket caused over heating since pressure of exhaust is stronger than water pressure it lead shortage of water.[/FONT]

 

[Barnacle Bill]

I am not sure if you have a Yamaha 30 sailboat or a Yamaha 30 HP outboard. I am assuming you have a Yamaha sailboat with some sort of inboard. My comments were pretty general for most inboards. You might want to get a second opinion from another mechanic in your area. If you end up replacing the head gasket and it still leaks, then the head is warped and they didn't solve the problem. If they replace the head gasket and it seals properly, you want to make sure the system is properly pumping water through the engine and out the exhaust or it will overheat again. When you start your engine, the first thing to do is look to see if water is coming out of your exhaust. That is an indication that the water is flowing properly. If it is flowing properly, then the raw water system (water from the lake or sea) is working, but if it still overheats, then I would troubleshoot the closed water cooling system, if it has one.

 

[Barnacle Bill]

Not sure how your engine is situated in your boat. Don't know how many cylinders you have or where the head is situated (can be on top, or on the side, etc.). One would think that you do not have to pull the engine to get at the head, but I am not looking at the motor. That is why you might want to get a 2nd opinion if you think your current mechanic is not being up front with you. Sometimes it seems the boat is built around the inboard and accessibility is next to impossible. If this is the case, they might have to pull the engine to get at it. That might be why the labor cost seems so much.

 

[remo7e]

Yes, it's a Yamaha 30 sailboat with a 12hp Yanmar diesel. Problem is, I'm here in Japan and at the mercy of a Japanese marina. The first time I took the boat there was when I bought her. They were supposed to repaint the bottom and change the oil. When I went to get her, they were replacing the impeller since it wasn't drawing in cooling water. I asked if they had checked to see if the intake was clogged and they were insulted that I'd even ask. Six hour later, I motored home with no problem. The next day I dove under the boat (no small task in October) and found that they had put the boat, still wet, on the carriage and it had pulled the padding off with the paint. I found pieces of the padding in the intakes. Yes, it was just plugged. They had also broken off the knot meter launching her. Needless to say, I have little to no confidence in this shop.
The engine is located under the v-berth. I suspect I will have to raise the engine. The American in me thinks that they should correct their mistakes without charging me full price.

Thanks for your help.

 

[Barnacle Bill]

Sorry that you are having so many problems. It is hard for me to comment on the performance of the marina that has been working on your boat, but it sounds as if some of their practices might be questionable. I would hope they would be honest with you despite the cultural differences and also, if they messed up, they would be responsible for any errors on their part. I guess if there was an alternative boat yard around to work on your boat you might try them out. I can imagine that if you are in a situation where you do not have any alternative marine services, you have to be diplomatic and try to get a reasonable understanding with them so you can keep them on your side so that you are not a victim of neglect on your part because you don't get a long with them. It can happen anywhere, I guess. At least in Japan you can get parts for Yanmars easily since they are built there. Good luck. You sent me a private message (it was announced), but never figured out how to access it (at least yet).

 

[remo7e]

Thanks again. I haven't heard back from the marina today but, like in America, there are many holidays this time of year. I am about 90% decided I will sail the boat back to my marina and find an honest diesel mechanic to do the work. Even if I pay him the same amount, I won't be paying the person who caused the problem to fix the problem. If you ever need any hard to find parts from Japan, let me know.

 

[Yamaha 33]

WE used to own a 1984 Yamaha 30 MKII. This boat had a Yanmar 2GM under the cockpit (not V-berth). Anyhow, although you might have had some padding from the cradle sucked up your raw water intake for the Y-12 you have (I believe you suggested this in a response you made) you should probably check the raw water pump belt tension. In fact you might want to replace the impeller as good measure after shelling out $2K. I think you should definitely get the head planed. I saw a local ad in BC where someone seems to have stuffed a 3GM under the V-berth into a Yamaha 30. Its a compact diesel.

 

[nickpollock]

YAmaha 30 over heat

Hi
I have a Yamaha 33 with a Yanmar YSM 12 under the V berth I have removed the head in less than 1 hour on my own with no special tools Though mine was in OK condition things not rusted or corroded up
This is a single cylinder horizontal engine
In Hong Kong cylinder heads for this engine are avilable at around US$ 100 I believe they are Taiwanese copies Friends have used them & are so far still operating The danger of machining the head is that the compression ratio may be raised too far
I would be inclined to get a new head & transfer you valves etc accross or get new ones depeneds on the cost in Japan
I would certainly avaoid the guys that gave you the grief in the first place
These are extremely easy engines to work on even removing the piston & liner can be done without removing the engine from the boat
Good Luck

nick

Thanks again. I haven't heard back from the marina today but, like in America, there are many holidays this time of year. I am about 90% decided I will sail the boat back to my marina and find an honest diesel mechanic to do the work. Even if I pay him the same amount, I won't be paying the person who caused the problem to fix the problem. If you ever need any hard to find parts from Japan, let me know.

 

[remo7e]

Just to have a little closure here: After 3 weeks of waiting for the 3 day job the marina had promised me, they emailed and were 'surprised to find the problem wasn't with the head gasket, but was with the water pump." I explained to them that I was not at all surprised, considering I had sent the above listed 8 things that I wanted them to check before they replaced the head gasket. Anyway, I felt like I was paying ransom to get my boat back. It is running great now and I've had several relaxing sails on Tokyo Bay (relaxing is a relative term when you are dodging the world's 2nd busiest shipping lane).

Thanks to everyone that gave me advice and information. It was greatly appreciated.