Yanmar 3ym30 shaking a lot after some regular maintenance

[psousa]

Hi there!

So, few weeks ago I called Yanmar techs because I couldn't engage the forward gear when the engine gets warm (after one hour or something working, I can engage once in 10 failures). They told me, by the smell, previous maintenance guys used wrong oil on the gearbox and now he needs to take it out to open and replace the "cone drive". He borrow me one so I can go on holidays. Also he changed the belts and the "escape elbow" (don't know if it's the right name in english).
After replace the elbow, the 2 belts and put his company gearbox, we started the engine and it shakes a lot. I told him immediately it was not like this before. He increase the idle revs a little bit and told me probably it's his gearbox not working well and also I probably need to replace the engine mounts... Ok... I went on holidays.
But the engine kept shaking too much:
1. too much when idling
2. A LOT when I engage forward without speedup
3. much more than before when under power, but not as much as on idling or engaged without power
But I went on holidays anyways anyways...

When I return he decided to change also the dumper before put back my gearbox (at the end he didn't replace the cone drive, only cleaned it - probably it was only a matter of changing gearbox oil as some other mechanic told me, but what should we do when a guy which is suppose to work with this every single day tells you he needs to take it and open it?!?.
When they were connecting the gearbox to the propeller shaft, things where not aligned (?!?) and he needs to unscrew the mountings and realign the engine... Don't understand why suddenly the engine needs to be realigned, but it's not my job.
After installing my gearbox, the engine keeps shaking. A lot!
Also start leaking oil underneath (never ever I saw a drop of oil under this engine!!!).
Also I found the water pump pulley not aligned (very unaligned!). Don't know how it gets like this but it was only a matter of screw it better.
This guy is a Yanmar mechanics. Just to note. I only work with authorized mechanics. It was the same with my previous Volvo Penta.

Today I decide to take the boat to another marina so other Yanmar techs can look to it. The to-do list is (but this is a opinion as they said they will 'start' doing this on this order in order to try to find the problem... this is something very nice to listening...):
1. one injector can be malfunction and producing this shake so they starts from here: take them out and ask someone to clean them...
2. change the mountings
3. clean the engine outside and observe carefully where the oil leaks are. It seems to him to be coming from the cylinders head (I think it was what he said), but need to carefully check. Then they decide how to fix them.
These guys told me these issues has nothing to do with the previous maintenance and it was a coincidence. I don't believe too much on coincidences when we are talking about combustion engines, but the truth is, so far, I have no reason to doubt on them and they spend a lot of time looking carefully to the engine and charged me nothing! Anyways these guys are the Yanmar importers so all others buy parts to them, including the guys which "fixed" my gearbox, so they will never say nothing wrong about their customers, right?!

The engine is now 998 hours. My gearbox was removed with 960 hours. Shake starts here, at this point (when they put the borrowed gearbox, replaced the belts and the elbow).
Oil leaks starts few days ago after they reassemble my gearbox and moved the engine to realign it with the shaft.

I was checking the manual and, for 1000 hours and besides other things, they recommend:
Fuel system
. Check the injection timing (nobody mentioned this to me) <- could be this the reason of the shake?!
. Check the injection spray condition (this will be checked with the injectors removal, right?)
Cylinder, head, etc.:
. Retighten all major nuts and bolts <- could this be the origin of the oil leak (maybe they got loosen because of the shake)?
. Adjust intake/exhaust valve clearance

What is your opinion about all this?

Thank you very much!

 

[RichardS]

Which country are you based in Psousa?

Unfortunately, I think you are being conned left, right and centre and in the UK I would probably start to think about my legal options but that might be irrelevant.

It sounds to me as thought the original con-man who did all the unnecessary work on the gearbox has screwed up the engine alignment so I would probably start with just that and get that 100% right before starting on anything else which might just compound the issues.

Sorry.

Richard

 

[Spyro]

Far too many issues and variables for anyone on a forum to diagnose. Some suggestions, sounds like the cylinder head was not removed so if an oil leak from there nothing to do with previous work. I think you might be referring to the exhaust elobow that wouldn't cause any symptoms you mention so rule that out. belt replacement shouldn't affect anything but may cause a burning smell if slipping. the vibrations may be because an injector is faulty but they wouldn't have been removed for any of the work you mention. The gearbox does seem to be the most likely culprit. It's a bit of work to put the old one back to prove it and even if you could it could be a damaged shaft bearing that's causing the movement.

 

[vyv_cox]

I suggest that your engine and gearbox are suffering from 'soft foot'. When the gearbox was replaced the man who did it left one mounting loose, so that the assembly is sitting (mostly) on three feet instead of four. You may be able to detect which one yourself without using any of these 'experts'. Tighten the mounting that is soft and the shaking should stop. Of course, all this may have led to a misalignment problem that will also need to be addressed.

 

[psousa]

I think i found the oil leak. There was oil around the yellow oil cap, on the left side of the engine. Because I can't close it more, I put some absorbent paper around it and after my last exit there was some oil on this paper and no oil underneath the engine but I want to check it again before I decide this is the source of the oil. By the way, I check the oil frequently and it's on the right level. Not so high neither low.

The gearbox does seem to be the most likely culprit. It's a bit of work to put the old one back to prove it and even if you could it could be a damaged shaft bearing that's causing the movement.

I have the 'old one' already. My own gearbox, the one which they took out to 'fix'. Before they took it out, the engine didn't shake. They took it out and put a borrowed one. The engine shakes. They took out the borrowed one and put mine back. The engine keeps shaking. I mean, now it's shaking with both gearboxes.

I suggest that your engine and gearbox are suffering from 'soft foot'. When the gearbox was replaced the man who did it left one mounting loose, so that the assembly is sitting (mostly) on three feet instead of four. You may be able to detect which one yourself without using any of these 'experts'. Tighten the mounting that is soft and the shaking should stop. Of course, all this may have led to a misalignment problem that will also need to be addressed.

I don't think so. They didn't touch the mountings when they replaced my gearbox by the borrowed on. They only changed the mountings (the engine/shaft was 'suddenly' unaligned...) when they put back my gearbox after 'fix' it. And the engine was shaking immediately after the 1st operation. Anyways I'm going to check the mountings by my self.

Friday I've added one of those liquids to clean up injectors of diesel engines on the cars (suggestion of the Yanmar importers engineer). I don't believe on these stuff but as the engineer told, 'bad, it wouldn't do!', so lets give it a try.

Just want to note that I'm very surprised (or maybe not...) that I had 5 "specialists" looking to this engine and nobody saw the unscrewed raw water pulley and the oil leak source! I think this says a lot...

 

[psousa]

To close this and after other mechanics (Yanmar) come on board:

1. one of them increased the idling revs and it's back to normal (no more shake). So the engine it's like before. And it's true: everyone says I need to change the mountings but the shaking problem was only because the first mechanic readjusted the idling revs. So the problem was already there but I didn't noticed it because of the revs; fixed (but i really need to change the mountings, maybe next April/May, before the season);

2. Oil was leaking from the left yellow cap (for some reason it has no o-ring anymore); one of the mechanics gave me one; partial fixed (see bellow);

3. other mechanics found the shaft retainers were leaking gearbox oil (circular yellow oil drips after engine works and result in some light yellow lub accumulation on the back) and they said it could be related with the gearbox opening by the 1st mechanics; 1st mechanics change them as per my request; partial fixed (see bellow);

4. elbow were not original; were a 'refit' one (in spite of I've paid for an Yanmar original one, as per my request I only want original Yanmar parts and it was listed on the invoice) and it was already having salt close to the seal/joint, some of the mechanics found it; 1st mechanics changed it as per my request (huge difference between both, mainly on the color! the first one was painted); fixed;

5. pulley was not aligned but it was a matter of screw it better; fixed;

It's awesome as if you just accept everything they say, you are cheated as hell! I call these other guys to come on board. To have one of these Yanmar mechanics on board I was moving my boat to another yard which took me one weekday morning! But I did it because I know things were not good. After all these guys come on board, I've sent a report to the 1st mechanics, at the same time I did a half of the invoice payment. Ask them to fix the retainers and the elbow and then I pay the other half.

So they did. They came last week and fix what I've asked. Didn't pay yet because want to test everything. Seems good but, after 6 hours working with the engine between 2.5 a 3k revs, this weekend, I found:

2. still have 2 or 3 drips of oil coming from the back of the engine... at first sight looks like it's coming from the top of the engine, maybe from the top yellow cap but I need further investigation. If so, I'll replace this replace this o-ring cap too. Hope it's not the rear main seal of the engine failing...

3. few circular drips of gearbox oil are at the back... don't know if it was some oil still there or it's not yet fixed. I'll wait a little bit more.

Conclusion: my original problem (forward not engaging well every-time when the engine/gearbox oil is warm) was so easy to fix by just replacing the old and incorrect oil, ends up with a extraction/opening of gearbox (to conclude the problem was not caused by the cone clutch, they kept the same), replacing of the damper and all this mess because they want to change EVERYTHING ALL THE TIME, they allwasy want to take the long path and heavy way, just to justify huge amounts of money! Related or not, coincidence or not, it happened to me! A huge mess!
Be aware and don't quit!