YANMAR 3YM30 ENGINE MOUNT REPLACEMENT

Vessel: Southerly 110 2006, based in Hovås Marina (South of Gothenburg)

2  ELLEBOGEN 75 (Ref. 128270-08341) and 2 ELLEBOGEN 100 (Ref. 128377-08351)

The main mission of a boat’s engine mounts is to secure the engine seat by isolating the vibrations generated by the engine itself and absorb any shock and vibration when the ship is in motion.

In addition to the noise and discomfort on board, the afore mentioned vibrations can generate wear and tear on all boat bindings, from the screws in the furniture and fittings to the electrical system even causing damage to the steering and rudder systems over time.

Case study: Southerly 2006. Yanmar 3YM30 engine

We will start by exploring the details of a real case in which the owner of a sailboat specifically a Southerly 110 from 2006. The engine is a Yanmar 3-cylinder reference Yanmar 3YM30, measuring 10,82 meters (35,50ft) in length and with a width of 3.6m (11,81ft) giving it a total displacement of 6980Kg.

Designed by Rob Humphreys and built as an ocean-going vessel by Northshore Yachts in England. With the keel up, the Southerly 110 has an extreme shoal draft of only 2 feet 4 inches! With the keel lowered all the way, the S110 draft is an impressive 7 feet 2 inches. The keel is fully adjustable to any depth you wish at the push of a button. The twin rudders provide exceptional tracking on all points of sail.

This Sailboat well maintained and properly stowed can accommodate up to 5 people in comfort.

PROCESS OF INSTALLATION

1. IDENTIFICATION

The first step is to identify the engine reference. This reference is on a plate attached to the engine cylinder head cover.

 Fig 1: Yanmar 3YM30 engine nameplate.
Fig 1: Yanmar 3YM30 engine nameplate.

Then, we must identify the reference of each flexible engine mount on the Yanmar engine. They have a number written on the rubber label that is visible on the side of the flexible engine mount which can be marked as 75, 100, 150 or 200.

Fig 2: Online engine selector.
Fig 2: Online engine selector.

If you do not know which engine mounts correspond to your Yanmar engine, you can look for the reference number in the Yanmar engine selector section of our website: https://www.ellebogen.com/us/shop-online/

2. DISASSEMBLY

If the drive shaft is well aligned, it is important to ensure it remains firmly in place. To achieve this, we can place, for example, a wooden board under the shaft, and proceed to release the bindings between the shaft and the transmission.

Fig 3: Secure position and release the shaft.
Fig 3: Secure position and release the shaft.

Once this step has been completed, we can start replacing the flexible engine mounts. In this case, the 3YM30 model is placed in following position over the engine mounts:

Fig 4: Sketch of the position of each mount on the Yanmar 3YM30.
Fig 4: Sketch of the position of each mount on the Yanmar 3YM30.

With the engine secured and ready to be raised, the fastenings of the marine engine mounts must be loosened.

Fig 5: Loosen the fastenings from the flexible mounts.
Fig 5: Loosen the fastenings from the flexible mounts.

3. RAISING THE ENGINE

With all the fixings loosened, the engine has to be lifted and the old mounts replaced with the new ones, one by one, looking at the references of on the rubber label.

In this case the owner of the boat Mr Roger Börjesson, showed excellent preparation and professionalism by carrying out this part of the process using an electrical winch.

Tip: It is recommendable that you use a double wire function at this point as this reduces the lifting speed by a half. It is especially useful to keep in mind the fact that you only need to lift the engine at a slow speed and to a height of about 10 cm.

Fig 6: Engine lifting process using an electric winch.
Fig 6: Engine lifting process using an electric winch.

4. MOUNT REPLACEMENT

It is also useful to note that each new engine mount has the leveling “H” at the same height as the old one. This step insures, that the driveshaft remains well aligned.

Fig 7: The new mount must have the same H dimension.
Fig 7: The new mount must have the same H dimension.

At this point it is important to note that in some installations, the levelling nut may be lower than the 12mm thick standard washer found in Ellebogen mounts.

Fig 8: On the left the standard 12mm height nut, on the right 10mm height nut that was on the “old” mount.
Fig 8: On the left the standard 12mm height nut, on the right 10mm height nut that was on the “old” mount.

If this is the case, we recommend using the nut from the “old” mount or  using the extra low height nuts which are included in the Ellebogen flexible marine engine mounts kit.

http://ellebogen.com/elle/wp-content/downloads/extra/Extra-low-height-levelling-nuts.pdf

In some cases, this 2 mm height difference, may avoid problems between the driveshaft and the stern gland.

The picture on the left shows the levelling of the mount with the 12mm height nut, as can be seen the level has not been adjusted which could cause noise and vibration between the driveshaft and the stern gland.

 

Fig 9: Example of an unleveled engine mount.
Fig 9: Example of an unleveled engine mount.

Fig 10: Photo of the driveshaft and the stern gland.
Fig 10: Photo of the driveshaft and the stern gland.

 

5. SETTLING

After replacing the engine mounts, the engine must be lowered and left to rest for 48 hours to in order to allow its weight to settle into its new position.

Fig 11: Let the engine idle for 48 hours before starting the shaft alignment.
Fig 11: Let the engine idle for 48 hours before starting the shaft alignment.

6. ALIGNMENT

With the engine already in place, attach the two driveshaft discs and proceed with the alignment process.

Fig 12: Attach the two driveshaft discs.
Fig 12: Attach the two driveshaft discs.

It is necessary to level out the anti-vibration mounts, adjusting the levelling nut until the two discs are parallel to each other.

Fig 13: Axis leveling.
Fig 13: Axis leveling.

ADVICE:

Fig 14: Avoid a leveling higher than 3mm.
Fig 14: Avoid a leveling higher than 3mm.

The level between the base nut and the levelling nut should not exceed 3mm. Since the propulsion force of the engine can generate repetitive stress on the height adjusters and this can cause to shear by fatigue over time.

Fig 15: Avoid leveling higher than 3mm.
Fig 15: Avoid leveling higher than 3mm.
Fig. 16: Image of an original cracked mount.
Fig. 16: Image of an original cracked mount.

 

If more elevation is needed at this stage, it can be achieved by placing a metal plate below the mount, but in general this corrective measure is not very common.

To check that the two discs are in parallel, it is important to be able to introduce a gauge of 0.003́ ́/0.07mm on all four sides and it must be able to pass through without difficulties.

Fig. 17: Check axis leveling, with a gauge.
Fig. 17: Check axis leveling, with a gauge.

This is hard work, but it is important as misalignment of the driveshaft will cause irregularities, warping and displacement and therefore, noise and vibrations.

Fig. 18: Checking alignment with a gauge.
Fig. 18: Checking alignment with a gauge.

Sailing on the Baltic sea

Roger Börjesson, a Swedish sailor based on the South of Gothenburg and active helper (contributor) on Yanmar forums, always keen to help fellow Seamen by troubleshooting problems and finding solutions. An example of the brotherhood between Sailors.

Roger sails in the waters of Sweden, Denmark, Germany and sometimes Poland. The following links may be of interest for those who are interested in finding out more about sailing on these waters:

https://visitsweden.com/what-to-do/nature-outdoors/sports/sailing-sweden/

https://www.cruiserswiki.org/wiki/Norway

https://www.cruiserswiki.org/wiki/Sweden

https://www.cruiserswiki.org/wiki/Denmark

https://www.cruiserswiki.org/wiki/Poland

A job well done pays off, proof of this is in the video below where you can see Roger’s Yanmar 3YM30 engine after installation of Ellebogen marine engine mounts.

Ellebogen technical support guided Roger through the correct installation after which he wrote this message of thanks.

Fig 19: Feedback from the customer Roger Börjesson
Fig 19: Feedback from the customer Roger Börjesson

Text: In the worst case I can start the engine cold and leave it idling at a speed of 800 rpm. This would not have been possible before I changed the engine mounts. Best regards Roger Börjesson.

Thanks to Roger for this great feedback and of course, for his hard work, a real Ellebogener.