Towards fall of 2001 the well-served 1980 Volvo-Penta MD5A of our Senorita was becoming tired, spitting diesel fuel into the sea, and getting more and more difficult to start. Failure of the electrical side was the last nail: troubleshooting in the fall rain was not tempting.

Another motivational factor was that 7.5 hp had proven not quite enough when occasionally pushing against a strong wind and waves.

A new stronger engine was due, at a favorable cost, of course..

(Yes, I know that rebuilding the MD5 is an option. Adding the price of the piston, cylinder head + lining, exhaust header etc. totaled a handsome figure – and it still would have been an old engine.)

So I pulled out the MD5 and started looking for a replacement.

• New motor should preferably fit to the existing S110 sail drive unit (1.66:1 gear ratio) and engine bed, to avoid glass fiber jobs. The original 12"x 6" folding propeller should be used if possible.
• Motor should fit into the rather compact engine locker of Senorita
• Motor should be lighter than MD5: she was floating a bit tail heavy
• Fresh water cooling would give longer life and easier fall service (well; MD5 lasted a good 23 years…)
• And the price had some significance, too.

Little used V-P engines are pricey and, at best, a very cramped fit in Senorita’s engine space.

There are several manufacturers who offer an adapter to S110 sail drive. After some research, making dimensional drawings about the fit into available space, and looking at the service points of the engines, I took a closer look at the Kubota engines ‘marinated’ in France and UK, and ended up with a Kubota Beta 10.

It is a 2-cyl. 10 hp diesel with fresh water cooling, and it gives the max power already at 3000 rpm.

• The motor is available with an adapter for S110 from the factory
• The power and torque curves of Beta 10 coincide with those of MD5 in whole rpm range: therefore, even with the lower gear ratio of S110 (1.66:1) Beta 10 can run at the same rpm – and same prop – as MD5 which mostly is used at 1500..2000 rpm. Beta 10 then has power reserve up to 3000 rpm, which will help in head winds and waves.
• The engine is available with a shallow oil sump: no need to cut the engine bed for more space. Oil change pump is available as accessory.
• Weight saving of 20+ kilos
• The local rep promised to make mounting support irons which are 5 cm wider than standard, to fit directly over the old mounting posts of MD5.

The same engine is available as a 14 hp version, which gives power and torque at higher rpm: this engine would have required a new prop and/or a new gear ratio to run at optimum power range.

(Today, also Kubota Nanni and Sole appear to offer a 10 hp/3000 rpm version with S110 adapter)

The new engine, painted bright red, arrived to the local rep. I brought the S110 to him and he mounted to the flywheel a flex plate where the spline count matched that of the S110.