Abstract: Several embodiments of bilge devices for small watercraft that permit the use of small capacity bilge pumps and which ensure that the bilge pumps will not run dry during abrupt maneuvers are disclosed. This result is obtained by using a trap-like device that permits water to accumulate from the bilge but which restricts the escape of the water during abrupt maneuvers.

Abstract: Embodiments of restraining grommets for use with protective cowling of marine outboard drives through which various flexible elements such as control cables and hoses extend. The restraining grommet is formed with at least two openings made up of multi-part sections and at least one of which is slitted so as to permit ease of insertion and removal of the flexible element without kinking of them.

Abstract: A number of embodiments of exhaust gas sampling arrangements for outboard motors wherein a sampling port is positioned in a portion of the engine in proximity to the exhaust port and in an area where it will not pass through the cooling jacket of the engine so that the exhaust gas sample will be representative of actual engine running conditions.

Abstract: An improved flushing system for an outboard motor that is comprised of a flexible conduit that is connected to the coolant path for the cooling jacket of the outboard motor between the water inlet and the engine cooling jacket so that plugging of the water inlet and water outlet during flushing is not required. The flexible conduit has a hose-type fitting at its open end for attachment to a hose for flushing purposes, and also for attachment to a closure plus fixed to the tray of the outboard motor protective cowling for closing the flexible conduit when not in use.

Abstract: A number of embodiments of engine induction system configurations for adapting four-cycle, multi-cylinder engines for use in small, personal watercraft. This is accomplished by canting the engine at an angle to a vertically extending plane and positioning the induction system on the upper portion of the cylinder head. Various configurations of manifold and carburetor locations are disclosed so as to achieve this purpose.

Abstract: A number of embodiments of personal watercraft having catalytic exhaust systems for treating and purifying the exhaust gases. In all of the embodiments, the catalyst is positioned and disposed so as to be protected from water. In addition, arrangements are provided for cooling the catalyst, for circulating ventilating air across it, for isolating it from other components such as the fuel tank, and for permitting its flushing with fresh water after operating in a salt water environment.

Abstract: An engine air-fuel ratio control system for a multi-cylinder engine that employs a fuel-air ratio sensor which is associated with only one cylinder. The other cylinders are operated leaner than that with which the sensor is associated. Also, the system can operate on an open control, and when switching from open control to feedback control, the incremental adjustments in fuel amount are initially made smaller and for a longer time period so as to reduce overshooting and hunting while permitting quick recovery during subsequent feedback control operation.

Abstract: A number of embodiments of feedback control systems for maintaining the desired air fuel ratio in a marine propulsion engine that has an exhaust system for exhausting the exhaust gases to the atmosphere through an underwater exhaust gas discharge and wherein the discharge is adjustable relative to the associated watercraft. Hull conditions which will change the engine performance are measured and the amount of fuel air ratio supplied to the engine by a feedback control system is varied, depending upon the sensed airflow and the sensed condition that may affect engine performance and, accordingly, the ideal air fuel ratio. Spark ignition timing is also changed and the air fuel ratio may be corrected depending upon exhaust back pressure.

Abstract: A water-removal assembly for removing accumulated water from the bilge of a hull of a watercraft that includes a jet propulsion unit with an impeller. The water-removal assembly includes a water pickup provided in the engine compartment. A means for removing water from the engine compartment and preventing water from entering and syphoning into the engine compartment is connected to the water filter by a first conduit. The conduit connects the water removing and preventing means to a water discharge point in the jet propulsion unit so that water is pumped from the bilge. The water removing and preventing means includes a check valve that allows water to flow in one direction so that water is prevented from entering the bilge. A weep hole is provided in the water removing and preventing means to prevent syphoning from occurring in the water-removal assembly.

Abstract: A number of embodiments of feedback control systems for maintaining the desired air fuel ratio in a marine propulsion engine that has an exhaust system for exhausting the exhaust gases to the atmosphere through an underwater exhaust gas discharge and wherein the discharge is adjustable relative to the associated watercraft. Conditions which will change the back pressure in the exhaust system are measured and the amount of fuel air ratio supplied to the engine by a feedback control system is varied, depending upon the sensed airflow and the sensed condition of the exhaust outlet that may affect back pressure and, accordingly, the ideal air fuel ratio. Spark ignition timing is also changed and the air fuel ratio may be corrected depending upon exhaust back pressure.

Abstract: A jet propulsion unit for a watercraft that employs a pair of counter rotating impellers that are disposed immediately adjacent each other so that the need for straightening vanes is eliminated. The impellers are driven by a bevel gear transmission to rotate in opposite directions, which bevel gear transmission is contained within the jet propulsion unit outer housing but forwardly of the flow path of water therethrough. This bevel gear transmission is driven by a single input shaft through a flexible coupling.

Abstract: An engine control arrangement including a fuel injector and an engine stop for disabling the running for the engine. In order to facilitate restarting, the fuel injector is permitted to continue to discharge fuel for a time period after the engine stop control is initiated.

Abstract: A lift arrangement for a marine engine permits the output shaft of the engine to be vertically oriented when lifting the engine. The engine configuration results in a center of gravity located along a vertical axis which passes through a flywheel assembly of the engine. The flywheel assembly sits above an upper end of the engine block. The lift arrangement includes a pair of hangers mounted to the top end of the engine with the flywheel assembly positioned generally therebetween. The hangers are attached on opposite sides of a central, longitudinal plane of the engine. The hangers also are arranged such that a line between the hangers intersects the central, longitudinal plane at a point proximate to the vertical axis which passes through the center of gravity of said engine. With a cable connected to each hanger, the engine can hang by the cable from a lift with its output shaft vertically oriented, without removing or interfering with the flywheel assembly.

Abstract: A feedback control system for a multi-cylinder engine using a combustion condition sensor that senses the condition in only one cylinder. The total air flow to the engine is measured and the amount of fuel supplied to other than the sensed cylinders is varied in response to known variations in air flow for a given engine running conditions. The sense cylinder has direct feedback control with no correction.

Abstract: A transmission system for a counter-rotational propulsion device is easily incorporated into an existing outboard drive of a watercraft to convert the outboard drive from a single propeller drive to a counter-rotational dual propeller system. The transmission system involves a first transmission which selectively couples an inner propulsion shaft with an existing drive shaft of the outboard drive. The inner propulsion shaft in turn drives a rear propeller. A second transmission of the transmission system is provided between the inner propulsion shaft and an outer propulsion shaft. The second transmission reverses the rotational drive direction input by the inner propulsion shaft so as to drive the outer propulsion shaft in an opposite rotational direction. The outer propulsion shaft drives a front propeller which spins in an opposite direction to that of the rear propeller, but asserts a thrust in the same direction as the rear propeller.

Abstract: An outboard motor having an fuel/air injection system wherein all of the major components of the fuel portion of the fuel/air injection system are contained within a sealed chamber having a fuel drain and the conduits that supply fuel to the fuel injectors are also contained within fuel collecting conduits so that any fuel leaking will not escape back to the atmosphere. In addition, the air pressure supplied to the fuel/air injectors is regulated and the air relieved for pressure regulation is returned to an air inlet device having a baffle for condensing any fuel in the regulated air and returning the condensed fuel to a vapor separator. The engine is of the V type and major components of the fuel/air injection system are positioned in the valley between the cylinder banks.

Abstract: A transmission for a counter-rotational propeller system of a watercraft outboard drive includes an improved clutch coupling which allows relative motion between a clutch and a portion of a clutch actuator, while reducing friction and wear between these components. The coupling includes an annular collar that is captured within an inner bore of the clutch. The ends of the collar are journaled within the bore for relative rotation between the collar and the clutch. Sufficient spacing also is maintained between the collar outer periphery and the inner bore wall to prevent contact between the collar and the clutch. A pin connects the collar to the clutch actuator.

Abstract: An outboard motor exhaust system that includes a simplified above-the-water exhaust gas discharge which is formed by an inverted U-shape tube that is detachably connected into the outer casing of the driveshaft housing so that the outer casing need not be formed with special passages for providing for exhaust gas flow.

Abstract: A catalytic exhaust system for an outboard motor wherein the catalyst is positioned in the drive shaft housing to remove this source of heat from the power head. However, the catalyst is contained within a sealed compartment in the drive shaft housing lower unit. In order to protect the catalyst from water, a trap section is positioned in the power head and this is water cooled by a source of water which has not passed through the engine for its cooling prior to delivery to the trap section. In addition, the guide plate that separates the power head from the drive shaft housing and through which the exhaust gases pass is also water cooled. An arrangement is incorporated for permitting replacement and servicing of the catalytic converter. Although both above the water and below the water exhaust gas discharges are employed, all gases flowing to the atmosphere must pass through the catalytic converter.

Abstract: Two embodiments of jet propelled watercraft having improved electrically powered trim adjustments. In one embodiment, the trim adjustment effects pivotal movement of the discharge nozzle of the jet propulsion unit and in the other embodiment the electric power operates a trim plate of the hull that extends beneath the jet propulsion unit.