Studies prove it: compared to modern cars, small outboard engines are real dirt slingers. It is estimated that the amount of unburnt oil released into the environment every year when operating these two-stroke engines is several times greater than the approximately 40 million litres of crude oil spilled during the Exxon Valdez disaster in the USA alone. This is why these small two-stroke outboards are no longer on sale in the EU. The Californian company Lehr Incorporated now offers another alternative to the well-known petrol four-stroke engines: instead of petrol, the engines burn propane gas. At the boat show in Miami, Lehr will be presenting two models with 2.5 and 5 hp, which could be suitable as slack water pushers for small dinghies and keelboats or as auxiliary engines for a dinghy. Later, the company plans to expand its range with engines of 10 and 25 hp.
Propane is a waste product from crude oil production and has several advantages over petrol, according to company president Bernardo Herzer. According to Lehr, propane produces 25 per cent less CO2 during combustion, up to 60 per cent less CO and reduces the emission of ultra-fine particles by 97 per cent.
"These engines are specially designed for the combustion of propane and therefore work very efficiently," says Herzer. Added to this is the significantly higher octane rating of the gas, which is 110 and therefore allows for higher compression and more efficient combustion. For comparison: Eurosuper is traded at 95 octane. Another advantage that should not be underestimated is the avoidance of dirty carburettors. The gumming up that occurs with conventional fuels is not to be expected with gas. Fuel problems are also avoided, which are a problem for many boat engines because they were not designed for the combustion of a petrol-ethanol mixture, keyword E10. Ethanol attracts water, which is deposited in the tank and damages the engine and the entire fuel system. To prevent this, additives must be added and the tanks must be inspected and cleaned regularly. Not so with propane: "No ethanol, no water, no additives, no problems," says Herzer.
Unlike compressed natural gas, propane as an engine fuel does not need to be highly pressurised, which means that the tanks are less complex and, above all, lighter. The 2.5 hp engine can optionally be operated with a small gas cartridge that is screwed into the engine head. Such cartridges are familiar from camping lanterns and small gas burners. Alternatively, propane gas cylinders can also be used, such as those commonly used for garden barbecues. Lehr has already licensed this technology for gardening tools (Fiskars) and used it successfully for generators, motorised scooters and go-karts. For this, the company was honoured with the EPA Clean Air Excellence Award and the Popular Mechanics Breakthrough Product Award.
The outboards are available in the USA from West Marine, among others, and cost between USD 999 (2.5 hp) and USD 1,956 (5 hp, long shaft). The website offers delivery abroad. There is not yet a German dealer. The fuel is available at any DIY store.
More under www.golehr.com
Distribution via www.westmarine.com
