Vessel: Jeanneau Sunlight 30 1989, in the Marina of Figueira da Foz , Lisbon Portugal.
2 ELLEBOGEN 75 (Réf. 128270-08341) et 2 ELLEBOGEN 100 (Réf. 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: Jeanneau Sun light 30. Yanmar 2GM20 engine
We will start by exploring the details of a real case in which the owner of a sailboat specifically a Jeanneau Sunlight 30 of 1989. The engine is a Yanmar 2-cylinder reference Yanmar 2GM20, measuring 9,15 meters (30.02 ft) of overall length and with a beam of 3.23m (10,60ft) giving it a total displacement of 3,100Kg (6834 lbs). The draft is 1,45m (4.75ft)
Designed by Daniel Andrieu and built by Jeanneau Shipyard in France. This sailboat belongs to the same range of Sailboats as the Sun Odyssey 31 or Sunfast 31.
This Sailboat well maintained and properly stowed can accommodate up to 2 persons in comfort.
After noticing that the engine was showing too much smoke and signs of overheating, the owner of the boat decided inspect the engine. A crack on the cylinder head was found. During the maintenance operation, he discovered that one of the flexible engine mounts showed some “age” symptoms (more information: https://www.ellebogen.com/us/how-to-detect-when-marine-engine-mounts-need-to-be-replaced/) and decided to change the 4 of them.
PROCESS OF INSTALLATION
The first step is to identify the engine reference. This reference is on a plate attached to the engine cylinder head cover.
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.
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/
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.
Pictures of the removal of the engine and being lifted with a crane for full inspection.
Once engine was repaired, the flexible engine mounts were placed. In this case, the 2GM20 model is placed in following position over the engine mounts:
Once the engine was repaired and painted was installed on the engine bed
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.
With the engine already in place, attach the two driveshaft discs and proceed with the alignment process.
It is necessary to level out the vibration isolators, adjusting the levelling nut until the two discs are parallel to each other.
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.
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.
This is hard work, but it is important as misalignment of the driveshaft will cause irregularities, warping and displacement and therefore, noise and vibrations.
Sailing on the Portuguese coast
Mr Renato Braz, a Portuguese sailor based in Lisbon. He is an 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.
Renato sails in the waters of Lisbon and his aim is to travel to Azores, Canary and Madeira islands. The following links may be of interest for those who are interested in finding out more about sailing on these waters:
A job well done pays off, proof of this is in the video below where you can see Renato’s Yanmar 2GM20 engine after installation of Ellebogen marine engine mounts.
The below video shows the vibration level on the 2GM20 with the Ellebogen flexible engine mounts.
Ellebogen technical support guided Renato through the correct installation after which he wrote this message of thanks.
Thanks to Renato for this great feedback and of course, for his hard work, a real Ellebogener.