Abstract: Several embodiments of automatic trim controls for marine outboard drives for maintaining the optimum trim angle under all running conditions. The velocity of the watercraft is determined and the outboard drive is trimmed up as long as the velocity continues to increase and then is trimmed down so as to maintain the highest velocity possible for a given running condition. Several different computer programs are illustrated and described for achieving this purpose and a number of different embodiments of power units for controlling the trim condition are also described, some hydraulic and other mechanical.

Abstract: Several embodiments of induction systems for two cycle, crankcase compression, internal combustion engines employed for powering outboard motors. The outboard motor is supported for tilt and trim movement and the induction system is designed so as to extend from the intake ports of the engine in a generally rearward direction so as to be substantially unaffected by changes in trim angle and acceleration. The invention is described in conjunction with both V-type and inline type of engines.

Abstract: An outboard motor having an air compressor for delivering compressed air to a scavenging system for the engine. The air compressor is designed so that when the engine is not running, any moisture which may be present in the pumping cavity of the air compressor will drain out of the outlet opening of the compressor.

Abstract: An arrangement for protecting an engine from an abnormal condition such as overheating by slowing of the engine through periodic misfiring of the spark plugs. In order to prevent backfiring, the engine is stopped if the slowed condition is such that backfiring might occur.

Abstract: Several embodiments of automatic trim controls for marine outboard drives for maintaining the optimum trim angle under all running conditions. The velocity of the watercraft is determined and the outboard drive is trimmed up as long as the velocity continues to increase and then is trimmed down so as to maintain the highest velocity possible for a given running condition. Several different computer programs are illustrated and described for achieving this purpose and a number of different embodiments of power units for controlling the trim condition are also described, some hydraulic and other mechanical.