shaky Yanmar 1gm10

[jiris]

I will post a vid tomorrow, my idea of smooth, and a yachtsman's may well be very different things. I suppose in reality it is rarely if ever going to be at idle, and if we maintain our discipline about not using an engine it will be less of an issue - however I know we will end up using it just to get into the solent proper quicker, and to do so many other things rather than stare up at a slack sail praying for wind.

Besides of incorrect stiffness of the mounts, low idle revs, a bit of air in the fuel etc, the problem may be caused by improper distribution of the engine weight between the individual mounts. Yes, you do can achieve a correct alignment with the shaft by a variety of different combination of the weight resting on each mount. Ideally it should be the same on each of them - the simplest test is by a torque wrench on the adjusting nuts. I had this problem on my newly installed engine 2 years ago and managed to reduce vibrations by the above method to a negligible degree.

 

[sarabande]

Does the output shaft from the gearbox go directly to the prop shaft and stern tube. or is there a flexible coupling in between or a thrust bearing at the top end of the log shaft ? I'm trying to picture where and why the propshaft is wobbling.

Can I be really picky and check that the cutless bearing is not water-lubricated, and has a grease lube nipple as you indicate ? Usually it's the thrust bearing/stern gland that needs greasing.

 

[solent clown]

It's Ok chaps, I have two identical boats with identical engines, same shakiness on idle, but it is all fine at working revs, so it is just the usual Yanmar shuffle

 

[DownWest]

I think that cutless bearings are, by definition, water lubed.

 

[solent clown]

I think that cutless bearings are, by definition, water lubed.

absolutely, however the boat ia out of the water, so for the purposes of the test I spray greased it for its short run.

 

[mickywillis]

Thats interesting, how did you do that?

Use the Pela on the very last bleed fitting on top of the injector pump. I took the fitting out completely (its a bolt with a point on the end and a small hole drilled into it to allow air to escape when bleeding) fitted the Pela tube into the hole left by the bleed screw, and then pumped up. Within a minute or so, the diesel had drawn through both filters, the lift pump and then into the injector pump. Carry on drawing for a few more seconds and then replace the bleed screw. Start engine at a mid range revs and hey presto, fully bled!