Yanmar 2Gm20F shaking with New Yanmar Mounts

[Brinky63]

I replaced the old mounts with Yanmar mounts specific for the engine, 3 years ago. The boat is 15 years old and had the original mounts still. One mount was a bit worn so we changed all four.

After installation the engine shook a bit which the mechanic told me was normal since the mounts were doing their work. Thought a mount was to hold an engine in one spot and prevent it from shaking but I trusted the mechanic buddy of mine.

Last week i noticed a sound in the engine room when engaging the gearbox (forward or reverse) which was unknown. Upon further review i noticed that the noise came from the stuffing box when I turned the shaft by hand. Also noticed a nice ping pong size bulge on the hose which is not a good sign.

New mechanic tells me that the stuffing box is damaged due to the shaking of the engine which he does not think is normal.
Believe it better to change out the mounts. Anyone else out there experienced this before?

 

[kloudie1]

Symptoms sound like the guy who changed the mounts did not center the shaft in the stern tube and did not correctly align the engine.. Yanmar mounts are "soft" on purpose to let the engine move a bit. The aneurism in the stuffing box hose is serious .. in the very short term, it could be taped with "rescue tape" and only used until you can schedule a haul out to change it and check the shaft for a bend.. That is a rough one,

 

[Benny17441]

Were the mounts correctly installed? Was the engine aligned after install? How is the engine running other than the shake? What is wrong with the stuffing box, is it leaking, is it heating up, has it scarred the shaft?

 

[Justin_NSA]

I have no expertise in this area, but in theory I agree it's an alignment issue. The engine and transmission should be in line with the stuffing box, cutless bearing and prop along with a straight shaft.

 

[Brinky63]

Thanks all. Just hauled her out, will be looking at all of this in the coming days. I agree that it's most likely an alignment issue. Will keep you posted.

 

[FastOlson]

If the engine is old enough to need (and most of 'em will after about a thousand hours or so) new mounts, you should also replace the stuffing box hose. Those multi-layer specialty hoses also have a finite life.

 

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[Brinky63]

The update and findings are as follows: We found the cutlass bearing to also be completely worn. The packing in the stuffing box nut was in good condition. No damage to the shaft anywhere.The engine mounts were not installed in the correct position which prevented us from correctly lining up the engine with the shaft coupling. Also found the bolts on one engine mount not able to be tightened. All of the above was corrected and the engine lined up properly with the shaft coupling. Going into the water in two days, will see how much change we will see.

 

[Mike Oldak]

The update and findings are as follows: We found the cutlass bearing to also be completely worn. The packing in the stuffing box nut was in good condition. No damage to the shaft anywhere.The engine mounts were not installed in the correct position which prevented us from correctly lining up the engine with the shaft coupling. Also found the bolts on one engine mount not able to be tightened. All of the above was corrected and the engine lined up properly with the shaft coupling. Going into the water in two days, will see how much change we will see.

I'm starting to question our local diesel engine specialists. I had a bunch of work done and they left the engine with the fan belt eating into the water hose. They came and fixed it and then left the alternator belt shield sitting on the belt so it would eat into the belt as it turned. REALLY SLOPPY WORKMANSHIP. MY NEW engine mechanic found some other issues. So I guess just because they say they are diesel mechanics doesn't mean its true!!!

I'm about to have my 1984 H34 engine mounts replaced (probably for the first time), I'm letting my new mechanic do it but will be there to watch over him/her.