A fast post-immersion restart system for a marine propulsion unit

摘要

The propulsion unit comprises a piston 5 reciprocating in a cylinder 1 and a combustion chamber 2 with a spark plug 8 and a first drain port 9 which is selectively openable independently of the position of the piston. If the cylinder becomes flooded with water, it can be purged by opening the port 9 and moving the piston 5 so as to expel water through the port 9. Once all the water has been expelled, further movement of the piston causes gases in the cylinder to follow the normal swirl path and pass over the spark plug, thus drying it in situ. The first port 9 may be annular, surrounding the spark plug 8 (fig.2). A second port 10 may be provided to improve drainage. A starting aid can be introduced through the second port 10; once it has started, the engine can be run on a fuel (eg kerosene) less volatile than the design fuel (eg petrol).