for a length of time (such as leaving the engine running when pulling the boat out of the water or in some cases tilting the engine out of the water while running), the impeller is likely to be ruined in the process. Air cooled outboards Air cooled outboard engines are currently produced by some manufacturers, these tend to be small engines of less than 5 horsepower. Outboard engines made by Briggs & Stratton are air-cooled Closed loop cooling Outboards manufactured by Seven Marine use a closed-loop cooling system with heat exchanger. This means saltwater is not pumped through the engine block as is the case with most outboards but still has to be pumped through the heat exchanger Engine Stalls An outboard engine may stall if it does not have the correct inputs. Common problems that lead to stalling are electrical issues, low quality gas or clogged fuel filer. Other issues may include a damaged carburetor oil switch. Other outboard motoring method In Vietnam and other parts of southeast Asia a long-tailed motor design is used. In Vietnam these are called "May Duoi Tom" (Shrimp Tail Motor). The outboard motors, which can be smallish air-cooled or water-cooled gasoline, diesel or even modified automotive engines, are bolted to a welded steel tube frame, with another long steel tube up to 3 m long to hold the drive shaft, driving a conventional looking 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. 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. The pivoting design allows the outboard motor to be swiveled by the operator in almost all directions: Sideways for direction, up and down to change the thrust line according to speed or bow lift, elevate completely out of water for easy starting, placing the drive shaft and the propeller forward along the side of the boat for reverse, or put them inside the boat for propeller replacement, which can be a regular occurrence to the cheap cast aluminum propellers on the often debris-prone inland waterways. This design is utilized to propel long-tail boats. Manufacturers Aquawatt Electric Outboard Motor Bolinder Briggs & Stratton - USA - Up