Abstract: An electrically powered automatic choke system for a turnkey outboard motor has a thermostatic override switch. The automatic choke feature is often not necessary, and sometimes not even desirable, when restarting the engine. The thermostatic override switch prevents the automatic choke from closing carburetor choke shutters when the ambient temperature near the engine under the cowl exceeds a choke deactivation temperature. A switch assembly is provided to retrofit engines on existing outboard motors.

Abstract: An air intake box for a four-stroke marine engine. The air box is generally U-shaped in configuration, including a lower section that is connected to the carburetor throat. The lower section extends forwardly from the carburetor and merges into an upper section via a reverse bend. The upper section extends rearwardly above the carburetor and terminates in a distal inlet end that is located at the rear of the engine. The air box reduces air intake noise, and results in cooler air being supplied to the engine, which enhances combustion.

Abstract: A marine drive has a reverse thrust cup on the propeller shaft between the propeller hub and the rear retaining nut. The reverse thrust cup permits the propeller hub to slide on the propeller shaft fore and aft. When the marine drive is in the forward direction the rearward thrust of the propeller forces the propeller hub to the forward position thereby directing engine exhaust out the rear of the propeller hub. Conversely, when the marine drive is in the reverse direction, the forward thrust created by the propeller hub forces the propeller hub to the rearward position thereby directing exhaust out a forward exhaust opening forward of the propeller blades increasing the reverse thrust of the marine drive.

Abstract: A blade having a concavely shaped leading edge is cut. The blade has first and second side faces, a tip profile and a root profile. Each profile has a first and second profile side corresponding with the first and second side faces. The cutter is positioned between the first root profile side and the first tip profile side. The tip profile and root profile are followed with two cutter portions of the cutter along the first root and tip profile sides toward the leading edge to cut the first side face. One of the cutter portions is translated around to the second profile side before the other cutter portion is translated to the second profile side, causing the formation of the concave leading edge. The tip and root profile is followed with the cutter, along the second profile side away from the leading edge to cut the second side face.

Abstract: A dual counterrotating propeller drive mechanism for a marine propulsion system incorporates a torque splitting device which consists of a differential gear means and a ratio gear means. The torque splitting device assigns a selectable fixed fraction of the engine torque to each propeller regardless of power, thrust, and speed conditions. The rear one of the two propellers adjusts its rotational speed relative to the front propeller in response to changes in the front propeller's wake and in this way maintains optimum propulsive efficiency over a wide range of operating conditions. Furthermore, precise matching of front and rear propeller parameters for a given application is no longer required.

Abstract: A marine stern drive unit is mounted aft of the boat transom on a rigid lift arm in a manner allowing the drive unit to be independently trimmed or moved vertically up or down. The drive unit is pivotally attached to the aft end of the lift arm for trimming movement about a generally horizontal axis and the lift arm is pivotally attached to the boat to rotate about a second horizontal axis such that the drive unit is moved generally vertically. The boat engine is preferably mounted transversely and power transmission from the engine to the drive unit is provided by a flexible drive belt which is supported by the rigid lift arm. Separate trim and lift movement is supplied to the drive unit by individual fluid cylinders. The trim cylinder operatively interconnects the drive unit with the boat hull or the forward end of the lift arm. The lift cylinder operatively interconnects the boat hull and the lift arm at a point aft of its pivotal connection to the boat.

Abstract: A system for optimizing the operating efficiency of a boat by balancing fuel consumption against cruising speed utilizes a comparison between engine speed and boat speed to effect automatic positioning of the drive unit. The measurements of boat and engine speed before and after an incremental change in vertical position or trim position are used to calculate the percent changes in boat speed and engine speed which, in turn, are used in conjunction with selected minimum and maximum incremental percentages to effect subsequent alternate control strategies. Depending upon the relative difference in the percent changes in boat and engine speeds, including adjustments based on the minimum and maximum incremental percents, the system will automatically continue incremental movement of the drive unit in the same direction, hold the drive unit in its present position, or move the drive unit an incremental amount in the opposite direction.

Abstract: A pulse balancing system is provided for a multicylinder two-stroke cycle internal combustion engine in which each cylinder is provided with its own mechanism for supplying an air-fuel mixture thereto. The vacuum pulse balancing system of the invention comprises a plurality of passages interconnecting each cylinder with one of the air-fuel mixture supply devices associated with one of the other cylinders, and one-way check valves provided in the passages. With the vacuum pulse balancing system of the invention, a vacuum pulse created by the piston in one of the cylinders is transferred not only to the air-fuel mixture supply device associated therewith, but also to the air-fuel mixture supply device associated with one of the other cylinders. This alleviates back pressure which may otherwise be caused in the air-fuel mixture supply device associated with the other cylinder due to the on-again off-again suction of air-fuel mixture therefrom to its associated cylinder.

Abstract: A transom extension assembly, particularly useful for smaller or auxiliary outboard motors, utilizes a pivotally connected 4-leg linkage and an operatively connected fluid power operator to lift the motor vertically with respect to the boat transom. The fluid power lift includes a mechanical latching apparatus by which the motor may be releasably held in its raised position and supported in its lowered position in a manner to relieve the hydraulic system from all other operating loads. The apparatus may include its own fluid pressure supply or may utilize fluid pressure from another boat system.

Abstract: A system for optimizing the operation of a marine drive of the type whose position may be varied with respect to the boat by the operation of separate lift and trim/tilt means includes an automatic control system which stores preselected drive unit positions for various operating modes and is operative to return the drive unit to any pre-established position by pressing a selected operating mode positioning button. The various operating modes may include cruising, acceleration, trolling and trailering position, any of which may be selectively modified to accomodate changes in both operating or environmental conditions. This system may incorporate other optimization routines and/or automatic engine protection systems to provide virtually complete push button operation for complex marine drive unit positioning mechanisms.

Abstract: A system for optimizing the speed of a boat at a paticular throttle setting utilizes sensed speed changes to vary the boat drive unit position vertically and to vary the drive unit trim position. The measurement of boat speed before and after an incremental change in vertical position or trim is used in conjunction with a selected minimum speed change increment to effect subsequent alternate control strategies. Depending on the relative difference in before and after speeds, the system will automatically continue incremental movement of the drive unit in the same direction, hold the drive unit in its present position, or move the drive unit an incremental amount in the opposite direction to its previous position. The alternate control strategies minimize the effects of initial incremental movement in the wrong direction, eliminate excessive position hunting by the system, and minimize drive unit repositioning which has little or no practical effect on speed.

Abstract: A position control system for a marine propulsion device senses an undesirable operating condition in the propulsion engine, such as low cooling water pressure at high speed or high engine temperature, to automatically lower the drive unit to a position in which the undesirable operating condition is likely to be alleviated. The system may include a logic timer circuit which will lower the drive unit for a short period of time, hold it in that position if the undesirable condition has been eliminated, or lower the drive unit further if the undesirable operating condition remains. The position control system may be incorporated into a conventional lift system, particularly a lift system used with a transom extension mounting assembly.

Abstract: A mounting assembly for an outboard motor includes a motor mount having a transom mounting bracket attachable to a boat transom and a motor supporting bracket spaced aft of and pivotally connected by upper and lower links with the transom mounting bracket to support an outboard motor wholly aft of the boat transom, and cylinder means for moving the motor supporting bracket relative to the transom mounting bracket to simultaneously move the outboard motor between raised and lowered positions in a vertical plane which extends parallel to the longitudinal dimension of a boat and to rotate the motor about a horizontal axis which extends perpendicular to the vertical plane. The movement of the outboard motor is provided by the motor mount being a quadrilateral structure wherein the lower link is shorter in length than the upper link and the motor supporting bracket is shorter in length than the transom mounting bracket.

Abstract: In a two cycle internal combustion engine (2), a turbulence generator (70) is provided by a freely rotating fan (72) in the fuel-air stream to the reed valves (16) which supply the fuel-air mixture into the crankcase chamber (8). The freely rotating fan (72) is driven by the fuel-air mixture flow and rotates to generate turbulence to provide more uniform distribution of the fuel-air mixture.

Abstract: A steering system for controlling an auxiliary marine engine includes an auxiliary engine steering cable operably connected to the hydraulic cylinder of the steering system for the primary engine so that linear movement of the hydraulic cylinder results in movement of the steering cable and pivotal steering of the auxiliary engine.

Abstract: A transom extension assembly for mounting an outboard motor in a spaced relation to the boat transom includes a quadrilateral linkage assembly in which each of the functions to trim, tilt and lift the motor with respect to the transom is provided independently. Each function is provided by a separate hydraulic cylinder means, but operating fluid pressure is supplied by a single fluid pressure source which may be mounted directly on the transom extension linkage.

Abstract: A small autoclave for bonding composite lenses comprising a cylindrical pressure vessel adapted to contain therein a lens tray for holding optical lenses aligned horizontally in a vertical array.

Abstract: A lens tray for holding optical lenses aligned horizontally in a lateral array wherein the tray is capable of holding lenses in such manner that the active surfaces of the lenses do not contact any foreign surface that may mar or scratch the active surfaces.

Abstract: A stratified-charge cross-flow scavenged two-stroke cycle spark-ignition engine (1) includes a piston (2) having a raised crown (6) with a baffle (7) and chamfered sides (8, 9) and reciprocal in a cylinder (3) between a combustion chamber (4) and a crankcase (5). Transfer passage structure is disclosed wherein a pair of elongated scavenging air passages (17, 18) extend between the crankcase and combustion chamber on opposite sides of a shorter fuel-air transfer passage (11). A pair of scavenging air inlet ports (20, 21) in the combustion chamber are adjacent the fuel-air inlet port (12) therebetween and substantially distally opposite the exhaust port (16). The scavenging air inlet ports face the baffle at its edges along the chamfered sides of the piston crown.