Lpg For Outboard Motors

Sydney Morning Herald

Friday June 9, 1989

By PETER FORBES

Displayed at the Sydney Boat Show is an invention that appears to be a world first - and it is Australian made. It is also one that should please both the "greens" and the captains of industry and politics.

It is a new conversion kit which adapts two-stroke outboard motors so they will run on liquefied petroleum gas (LPG), something not possible until now. (Although LPG is well established in cars, especially taxis, it has been restricted to four-stroke engines.)

Because the breakthrough cuts pollution, increases fuel economy and will probably sell well, it should please a wide range of people: the worldwide environment movement, the international outboard companies, the consumer, and the Treasury in Canberra when overseas sales begin helping the national balance of payments.

Ironically, the new two-stroke technology is a development which a major outboard manufacturer said could not be done, but a group of Australian Davids proved Goliath wrong.

The new technology is also a fuel-saver in an energy-conscious world and it is adaptable to two-stroke motors in general.

With this sort of market at its feet, the developer, the Australian-owned Melbourne company Gas Outboards International Pty Ltd, has been smart and holds worldwide patents.

In the meantime, it has tested the conversion unit successfully on a water taxi at Brooklyn on the Hawkesbury River. The Maritime Services Board has approved the technology for NSW and the first two retail units have been sold recently in Sydney.

These units, the first to be sold in the world, were bought by Sydney's Knox Grammar School, which will be operating two 115hp outboards on a large punt for the school's camp on the Hawkesbury.

As with land-operating taxis, the new technology makes more than a small dent in fuel costs and pollution. The developers say that, in LPG outboards, fuel costs are at least 50 per cent lower than with petrol engines and 25 per cent lower than with diesel. Carbon monoxide exhaust content is cut from about 8 per cent for petrol to about 1 per cent for LPG and, because the gas does not wash away the lubricating oil, engine life is longer. Less oil is also needed in the mix.

The developers say safety and reliability are improved because fuming is eliminated, and water and other contaminants cannot enter the pressurised tanks.

Wayne Saunders, the operator of the Brooklyn water taxi, says he saves about $19 an hour by using LPG in his two 115hp Yamaha two-stroke outboard motors. Petrol would cost him about $28 an hour; LPG is costing him $9 an hour.

Even a 136hp inboard diesel previously fitted to his former police boat cost him $12 an hour, and for this he got a cruising speed of 18 knots compared with 25 knots from his outboards, and a top speed of 25 knots against 35 knots on gas.

He says his fuel savings are about $20,000 a year since the switch, and with further development, there will be better burning of the gas and even more savings.

Saunders missed out on winning the patents for the new LPG system by a month. Instead of wailing about it, he contacted Gas Outboards and teamed with the company and the Shell LPG subsidiary, Go-Gas, in testing the new fuel system on his water taxi. He has also become the agent for distribution in NSW.

Unlike petrol, LPG needs no fuel pump. The pressure of the liquid in the tank sends it to a vaporising unit on the engine, where it becomes expanded to gas. Warm water from the motor prevents freezing during this process. A priming circuit enables starting of the motor and from there the pressure of the fuel takes the gas through a set of venturis to the carburettors.

From there, the vapour enters the engine in the usual way, with oil being injected separately to give the necessary oil fraction required by outboard motors.

Meanwhile, the oil giant Shell may soon market a new biodegradable oil which will go with the new technology and this should make LPG even more of a boon.

For the present, the technology is for bigger engines and is best suited for commercial use and long-run operations, but there is no reason why it should not become available for smaller engines and general recreational boating later.

Development will continue at Gas Outboards' central "test cell" at Wandin, in Victoria, and on the water at Brooklyn. Yamaha is watching developments closely.

Two of Gas Outboards' LPG-converted motors are likely to be going to Monte Carlo for display at the world LPG forum later this year, and the Sydney Water Police and a Sydney Harbour water taxi company are considering trialling LPG on some of their boats.

A standard conversion for a single 115hp Yamaha outboard, with single tank, is priced at $3,690. Gas Outboards is also investigating an engine rental operation.

Wayne Saunders can be contacted on (02) 4551781.

© 1989 Sydney Morning Herald

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