Outboard motor
An outboard motor is a propulsion system for boats, consisting of a self-contained unit that includes engine, gearbox and propeller or jet drive, designed to be affixed to the outside of the transom.
If one has a choice, these factors should be noted: Large outboards are affixed to the transom using clamps and are either tiller steered or controlled from the helm.
The smallest of these weigh as little as 12 kilograms (26 lb), have integral fuel tanks, and provide sufficient power to move a small dinghy at around 8 knots (15 km/h; 9.2 mph) This type of motor is typically used: Electric outboard motors are self-contained propulsory units for boats, first invented in 1973 by Morton Ray of Ray Electric Outboards.
These products have several advantages such as lower emissions, absence of ethanol-related issues, and no need for choke once the system is pressurized.
[4] Lehr is regarded as the first manufacturer to have brought a propane-powered outboard motor to market by Popular Mechanics and other boating publications.
[11] It was developed from 1903 in Grosse Ile, Michigan, with a patent application filed in 1905[12] Starting in 1906,[13][14] the company went on to make thousands of his "Porto-Motor"[15] units,[16] claiming 25,000 sales by 1914.
[18] Historically, a majority of outboards have been two-stroke powerheads fitted with a carburetor due to the design's inherent simplicity, reliability, low cost and light weight.
Drawbacks include increased pollution, due to the high volume of unburned gasoline and oil in their exhaust, and louder noise.
In 1962 Homelite introduced a four-stroke outboard a 55-horsepower (41 kW) motor, based on the four-cylinder Crosley automobile engine.
This outboard was called the Bearcat and was later purchased by Fischer-Pierce, the makers of Boston Whaler, for use in their boats because of their advantages over two-stroke engines.
[21] In 2012, Lehr inc. introduced some small (<5 hp) outboards based on modified Chinese petrol engines to run on propane gas.
Conversion of larger outboards to run on Liquified petroleum gas is considered unusual and exotic although some hobbyists continue to experiment.
[22] Boats built in the US have Coast Guard Rating Plates, which specify the maximum recommended engine powers for the hulls.
Even worse, if the water intake ports on the lower unit are not sufficiently submerged, engine overheating is likely, which can result in severe damage.
The optimal trim setting will vary depending on many factors including speed, hull design, weight and balance, and conditions on the water (wind and waves).
[24] The most common type of cooling used on outboards of all eras use a rubber impeller to pump water from below the waterline up into the engine.
Common problems that lead to stalling are electrical issues, low quality gas or clogged fuel filer.
In Vietnam these outboards are called máy đuôi tôm (shrimp tail motor), which are smallish air-cooled or water-cooled gasoline, diesel or even modified automotive engines bolted to a welded steel tube frame, with another long steel tube up to 3 m long to hold an extended drive shaft driving a conventional propeller.
The frame that holds the motor has a short, swiveling steel pin/tube approximately 15 cm long underneath, to be inserted into a corresponding hole on the transom, or a solid block or wood purposely built-in thereof.
[27][28][29][30][31] This drop-in arrangement enables extremely quick transfer of the motor to another boat or for storage – all that is needed is to lift it out.
