In the 1990s, Mercury had already tried to run their engine with gas. This solution, which consisted in spraying gas at the carburettor inlet, was never really convincing. In 2019, the American manufacturer returns with a product entirely designed for gas.
Presented at the 2019 Grand Pavois in its 5 hp version, this engine sees the disappearance of the carburettor replaced by a real LPG injector. Still built on the 123 cm3 single cylinder block (the same block used for 4, 5 and 6 hp power). This 4-stroke weighs 27.2 kg.
Apart from the specific connection that connects it to the propane cylinder, nothing differentiates this engine from a gasoline engine. It is also equipped with a tiller, a manual start with a launcher and even a starter. As on the petrol version, it enriches the fuel-air mixture. A safety device with an automatic gas shut-off valve in case of leakage has been added. To recharge the batteries, this engine is equipped with a 12 V 4 A (50 W) alternator.
The first water tests show a behaviour very similar to that of a petrol engine. If the thrust is the same, it is on consumption that we must stop. A 18.9-litre (5-gallon) propane cylinder provides 22 hours of cruising time (2500 rpm) or 10 hours at maximum speed (5000 rpm). That is a reduction of about 30% compared to gasoline. A good point for the environment.
Among the advantages of propane, in addition to lower fuel consumption, is the stability of the fuel, which will be much easier to winter than gasoline.
This motor is available in classic version (with 2 shaft lengths 381 and 508 mm) and Sail version (also with 2 shaft lengths 508 and 635 mm, but with a traction propeller for heavier boats). The 5 hp LGP will be suitable for fishing boats or small sailing boats.
On the price side, the propane version is more expensive than the petrol version since the 5 MLH costs 1,549 euros including VAT in petrol and 1,704 euros in propane, i. e. 10% more..
