New Finnish Boat Engine

VIRE 12

Original author: Kari Hermola

First published in Vene magazine, August 1981

Translated from the Finnish, with permission, by Mauri Lindholm (2004)

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Engine manufacturing hasn't yet died in Finland. The struggling Valmet Jyska works has brought to market a 12 hp big brother to the old well-known Vire 7. Is there still room for a 2-stroke petrol engine in this diesel era? A Vire is about half the price of a corresponding diesel engine. Just calculate the difference - for how many years could you cover the extra fuel costs?

For many years the Vire engine has divided boat owners into two groups. One group thinks it's not reliable, noisy and stinks! The other likes its simple construction and small size and especially its low investment price. There is no denying that some faults occur repeatedly in Vire engines but they result, without exception, from neglected maintenance. Users seem to have the strange attitude that a cheap engine deserves less maintenance than a costly one.

For a long time, Vire fans have been looking for a more powerful model that would serve as an auxiliary engine for bigger sailing boats, or even for a small fishing vessel. Bearing in mind the typical brief use of a yacht engine, a petrol engine remains a more economical alternative to a diesel, in spite of the higher fuel costs. In practice auxiliary engines are driven briefly and occasionally. The engine is driven too cold, and a two-stroke engine tolerates cold running better than a four-stroke.

A Vire engine is often criticised for its loud exhaust noise which carries far - several kilometres distance on a calm summer evening. However, the exhaust noise is reduced by using an exhaust pipe and a silencer of rubber, which are common today.

Appearance almost unchanged

At first sight the new Vire 12 doesn't differ much from the old engine. A closer look reveals a number of differences: -

• The engine is still single cylinder with an unchanged cylinder volume. The increased power has been produced by redesigning the cylinder head. Its internal channels are noticeably wider and better designed. The compression ratio has been increased, as well as the maximum power. The maximum engine speed is higher too. The motor tune-up is on the same level as that of outboard motors, the construction being more rugged.
• From the viewpoint of more reliable running, one major improvement is a change in the type of carburettor. The earlier engine utilized a diaphragm carburettor which also served as a fuel pump. For proper functioning, annual renewal of the membrane was almost a must. The major problem was that the carburettor was fitted with adjustable fuel nozzles. For most users, the temptation to adjust the fuel-air ratio to their own liking was too great. As result either jamming of the engine or clogging of the exhaust pipe occurred. The diaphragm carburettor has now been replaced by a fixed-nozzle fuel bowl carburettor, with a separate fuel pump.
• The exhaust side has also been updated. The exhaust gas collector behind the engine contains a water lock that prevents water ingress from the exhaust channel into the cylinder when stopping the engine. A separate water lock is necessary if the exhaust pipe is very long or if the engine is located below the waterline.
• The installation of control cables has also been made noticeably easier. There is no longer any need for a specially-constructed plate for remote control lines at the side of the engine, as the cables are attached direct to extensions beside the exhaust gas collector. Neither is there a need for fancy mechanisms or a mess of wires to connect the control lines to the carburettor.
• The choke control line is totally missing; the choke is now controlled electrically.
• The gear ratio has been changed to match the increased engine speed. The speed of rotation of the propeller is unchanged.
• Another annoying feature used to be breakage of the stud bolts at the propeller shaft flange. It occurred especially when driving a large propeller. The stud bolts have now been fitted with steel support bushes that prevent breaking. In addition, a limiting structure has been introduced on the flange in order to prevent extensive deformation of rubber sleeves when reversing at high power.

Still room for improvement

Although many of the old faults have been remedied in the new Vire, some more improvements could have been made: -

• Damping of the air intake noise is still unresolved. The sieve on top of the air intake acts more as flame arrestor, it cannot reduce the noise much. Noise damping would be important for users and would be not more costly than the present device.
• The electric system has remained modest. The present combined starter/generator ("Dynastart") should be replaced by a proper starter and a separate alternator, with enough electric power for today's more demanding running lights.
• The present flywheel magneto is reliable, although it can't be denied that maintenance is difficult. If, for any reason, bilge water rises to the level of the magneto, motoring ends instantly. Generally, removal of the fly wheel will be necessary, which during a voyage can be extremely difficult. A contactless CD-ignition system would be today's solution and presumably a less expensive alternative.

Practical experience

The Vire 12 started easily and ran at idle in a reliable manner. After some warming-up, the speed of a "Myrsky-Janne 700" with two people aboard was measured at 7.1 knots. The engine was clearly over-powered, as the boat accelerated fast and the maximum speed was already reached at 2/3 throttle lever position.

Exhaust noise was very low although there was only a standard rubber silencer. However, the noise from the air intake was annoyingly high.

The engine ran reliably too when hot. Neither longer running at low power nor running at idle caused stopping as before.

Overall the Vire 12 functioned pleasantly. As it's easy to install and low-cost it will certainly find its place as a common drive unit in small craft.

Technical Data

Translator's notes

The above text is an unofficial translation of an article issued in August 1981 in a Finnish boat magazine "Vene" (vene = boat). Permission was granted by the Vene magazine for use and free translation of the article. For more information about the magazine see http://www.vene-lehti.com

As to fuel, the Br.Eng. term 'petrol' or Am.Eng. 'gasoline' corresponds to 'benzin' in German, 'bensin' in Scandinavian languages (Swedish, Danish, Norwegian) or 'bensiini' in Finnish.

A curiosity: The alternative mixed fuel component that has been translated 'paraffin / kerosene' refers to 'petrooli' in Finnish, 'petrol' in Swedish. It is a vanishing fuel type, hardly available any more. As to its composition and viscosity, as a fuel it is between 'petrol' and 'diesel fuel oil', like the kerosene for aircraft or 'lamp oil'. Motor enthusiasts who need this type of fuel, once so common, for their old time engine can make their own "kerosene" by mixing petrol and diesel fuel oil.

The price indication 5950 FIM (Finnish marks) in the year 1981 corresponds to a figure twice that high in 2004 (average annual inflation presumed 3%) and expressed in Euros makes about 2000 EUR.