Boat: Makma 700, cruising through the beautiful Frisian Canals.

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

The aim of this report is to explain the case of a user of a Yanmar 3GM30 that had high levels of vibration on a Makma 700 and the steps to fix the vibration problem.

We will start first describing the details of the boat: It measures 7 meters (22,96ft) in length, with a beam of 2.65m (8.69ft), and a displacement of 1500Kg (3300lbs). It was designed by Aquatec in Wousend in the Netherlands.


The boat owner observes that the engine shows an unbalance when cruising around 2200 RPM. (Speed around 5.5 and 6 knots). The Propeller and shaft (bearings) have beenchecked and balanced. Transmission plus Yanmar engine at 100%, well maintained including valve adjustments and tested plus serviced injectors. Engine starts and runs great in good balance, with no vibrations at idle or under load.

Fig. 2: Gráfico de transmisibilidad. La línea amarilla se desplaza de izquierda a derecha según la velocidad de funcionamiento del motor, de ralentí bajo a ralentí alto.
Fig. 2: Gráfico de transmisibilidad. La línea amarilla se desplaza de izquierda a derecha según la velocidad de funcionamiento del motor, de ralentí bajo a ralentí alto.

Given the situation, we decided to have a look to the mounts and the installation.

The tricky aspect of this case is that if engine mounts work fine at idle, they also should work fine at 2200 rpm. If we look to the below transmissibility curve, they should work even better!

One of the areas that had a margin for improvement was the installation of the mounts. They were not placed fully on the engine bed. The mounts also looked like they had too much deflection.

The installation had too much levelling to our taste, around 12mm. This is something that can be very controversial. But to our point of view the lower the levelling the better.

One of the engine mounts had a section where the rubber was unbonded

Another mount had a crack that was very hard to see

We also noticed that the engine mount position on this mount was inversed.

The height of the mounts was measured also,  A and B is variable.  The Port front mount has a 10 mm gap and the starboard rear mount, 14 mm.


On the following link videos and pictures of the original installation can be seen



Mr Foppe Jasma, the owner of the boat and great contributor to the Yanmar engine repair discussion group in Fb decided to adopt the following fixing measures.


Unstalling the mounts

Once the Yanmar engine mounts were relieved of the load, the cracks could be seen. In the image below, the rubber has come off the metal. Corrosion and age played a big role here.


Installing new Ellebogen mounts

A 10mm metal plate was attached to the engine mount. The Ellebogen marine engine mounts were installed flat on the metal mount.

3.- Improvement in other areas.

  • New prop shaft seal and bearing.
  • Prop shaft aligned.
  • Injectors removed and checked. Brought to the Yanmar dealer all 3 needed to be readjusted output pressure was reported low around 10 to 15 bar to low.
  • Water pump renewed. Plus, all water hoses and thermostat renewed.
  • Diesel supply pump renewed.
  • Exhaust hose renewed.
  • Exhaust Elbow renewed.


“Boat launched in the water late April, 15 Hours done so far, and all seems to be coming together perfectly. No shaking vibration the original 22-year-old Yanmar 3GM30 runs like a dream.”  



The famous saying goes “God created the world, but the Dutch created the Netherlands”. This refers to the fact that large parts of the Netherlands are below sea level and used to be water. The picture on the left shows it all.

The canals in Holland were built to draw water from the land, to travel and transporting goods, and to irrigate.

The famous canals of Amsterdam are the consequence of good city planning and served not only to prevent flooding, but also as an additional means of transport to the city streets. In Leiden and Delft they were also built under the same idea, to serve as canals for transport. Today the canals are not only a means to travel, but we also find restaurants, houses where people live, etc.

If you are visiting Amsterdam or other major cities in Holland, you will want to spend some time on the canals. The history of canals is deeply integrated with the cities and tours, and most tour packages include the canals. 

Useful Links:

Charts and map :

VaarWater App: Helps you get the best out of your time on the waterways of Amsterdam. Alongside a boating map with routes through the city, up-to-date information about the waterways and opening times of bridges and locks, you can also create a profile for your boat to let your boating friends know where you are (and see where they are). In time, additional functions will be introduced including a one-to-one chat function that will let you chat with people on other boats via the app. The app is available to download in the Apple App Store and Google Play Store.

Waterways and objects :;0.384521;53.051120;9.613037