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Yanmar seized

6K views 8 replies 8 participants last post by  Omatako 
#1 ·
I have a 75hp turbo yanmar w/350hrs in a 41' ketch. I had the boat hauled and then splashed when the bottom was done. I then motored about 6 miles to my slip, docked the boat and returned to it one month later. Tried to start the motor and it had seized! It has always run great and did so just the month earlier. No sounds, or any indication of problems. Anyone have any ideas? I am having it pulled next week and will find out for sure but I sure hate boatyards and don't trust them!
 
#2 ·
Did the motor attempt to turn at all? I would check all possibilties befor writing it off as siezed and a total loss. There are many things that it could be. A corroded grounding wire, battery to starter connection...many more. I would have a trustworthy diesel mechanic come down to your boat and troubleshoot it.
 
#4 ·
I have had 2 different mechanics look at it and tell me it is seixzed. One of them poured Marvel Mystery Oil into the motor, let it sit for a couple of days and still couldn't break it.
I don't believe it is hydro locked because the last time I started it, it fired right up. The next time, it won't do anything at all.
I will look at it Monday for the first time, but expect I'll see the same. I would love to be present while they tear it down, after they pull it from the boat, but don't know if they will permit that "due to insurance".
I just can't figure out why it would seize.
 
#5 ·
cooling?

If all they did is haul it and paint the bottom, the only things I can think of are:

1. Was the engine water intake closed during this process. Did you overheat on your short trip, was it spitting raw water?

2. Do you have a raw water intake scoop? Did they paint sloppily and close this up (maybe painting over growth, etc).

3. Did the travel lift straps end up crushing and intake scoop and blocking it?

If any of these are true, you could close the intake seacock, remove the hose, and open it BRIEFLY to see if you get flow.

Wild guesses, probably wrong....best of luck. Never met a boat yard that did require close watching.
 
#6 ·
Before getting into any real work, pull your dipstick and make sure that there isn't metal on it and that there is oil. After that, I would start by trying to turn the engine by hand. I am not familiar with your specific engine but there is usually a bolt that you can get a breaker bar onto and turn it. If it won't turn, you need to release compression and try again. If it has a compression release, you can try this and if it doesn't, you will have to pull all of the injectors. If releasing compression lets it turn over, it was probably hydrolocked (just because it started well a month earlier does not mean it wasn't hyrdrolocked). If it spun freely with compression, then you have an issue with your starter.

If you cannot get it to turn even without compression, then you are probably looking at a seized engine in some form. The point above about raw water being blocked off is a very good one.

Good luck and let us know what it turns out to be.
 
#8 ·
I would suggest if you are handy at all that I would pull the injectors, and do further checking as well if this is a turbo style how is the turbo driven by belt, its possible the turbo could be at fault as don't know the engine set up. With all the engines I've worked with which have been sized and there has been a few, there hasn't been one I couldn't at least move a little. There is also a trick I've learned to get things moving, after you have inspected the engine with the injectors out, I would dissable the fuel system pour is hot transmission fluid in the cylinders where the injector's came out, let it sit for a bit then try. This fluid has away of releasing rings and getting by to drip down on the crank. I think that there needs to be more checking. If it is as you say what did the mechanic's say was seized, and how did they determine that. Best of luck.
 
#9 ·
If the crank shaft can't be moved at all from the front pulley, you're wasting time taking out injectors and all that stuff. Any engine that is not siezed will turn at least a little in either direction and if it has been standing there will not be enough compression in any cylinder to stop it moving. If it doesn't move, it is siezed, end of story.

Question is, is it siezed on the crank or in a cylinder? It could be either but my worry is why didn't an alarm go off? Either an overheat or low oil pressure would have caused an alarm to scream (assuming they're working).

The other thing that could have happened is a leak in the header or a sleeve due to corrosion that would cause salt water to leak into a cylinder or two. If this has happened then that/those piston/s will not be moved, forget about boiling oil and all those "fixes". Nothing deteriorates quite as fast as a cylinder sleeve subjected to salt water. I know, I have had this and in two days the engine could not be moved.

I suspect this is probably what happened and if so, then the yard is not responsible. Just my opinion but born of bitter experience.
 
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