Abstract: A marine propulsion system includes an outboard powerhead mounted to a horizontal mounting plate within a boat platform recess. A steering arm is attached to a yoke that extends through the transom plate for rotating an attached propeller drive unit. The yoke includes integral fluid paths for hydraulic cylinders coupled to the yoke to pivot the propeller drive unit, and for powerhead cooling water. A removable gearcase plate allows the outboard powerhead, the horizontal mounting plate, the steering arm and the yoke to be pre-assembled and dropped down through the boat platform recess.

Abstract: A four-wheel drive straddle-type all-terrain vehicle has a progressive limited-slip differential that functions as an open differential when the wheel speed differential is less than a predetermined threshold, or cutting point, and functions as a progressive limited-slip differential when the wheel speed differential exceeds the cutting point. The progressive limited-slip differential is able to transfer torque to the wheel with greater traction as a generally linear function of the wheel speed differential, meaning that the more one wheel slips with respect to the other, the more torque is transferred from the slipping wheel to the wheel with traction. The progressive limited-slip differential comprises a rotary shear pump that drives a piston against a pack of clutch plates. The force of the piston against the clutch pack locks the left and right axles together to provide optimal traction in slippery conditions.

Abstract: A watercraft having a turnable (i.e., pivotable) planing surface, preferably with at least one skeg projecting generally vertically downward from the planing surface. This structure is designed to provide improved steering performance of watercraft, particularly jet-powered boats, while minimizing drag. The turnable planing surface is formed by a bottom surface of a steering pad mounted beneath a jet propulsion unit. In one embodiment, the water jet propulsion unit is fixed (i.e., not turnable) and the skeg-bearing planing surface is turnable relative to the water jet propulsion unit. In another embodiment, the water jet propulsion unit is turnable relative to the hull centerline (e.g., in the manner of an outboard engine) and the skeg-bearing planing surface is fixed relative to the water jet propulsion unit (i.e., the skeg-bearing planing surface turns in unison with the jet propulsion unit). The planing surface may optionally have strake-like sides.

Abstract: A snowmobile includes a chassis having a generally reduced length and a snow flap pivotally attached to the rear portion of the chassis, above the track system. The track system extends rearwardly beyond the chassis, and the snow flap shields the track system above and behind from spraying snow. The snow flap is linked to the track system so that as the track system moves through a range of travel relative to the chassis, the snow flap pivots relative to the chassis with the track system. This configuration prevents damaging contact between the tread and the undersurface of the snow flap and/or the chassis. The reduced length of the chassis decreases the weight of the snowmobile and the polar moment of inertia, thereby improving turning performance. A bumper extends from the snow flap and can be used to lift the rear of the snowmobile more easily.

Abstract: A watercraft includes an engine having an output shaft. A coupling structure is provided on one end of the output shaft. A driveshaft has an engine connecting axial end portion. The engine connecting end portion provides a first cooperating interlocking structure. A resiliently deformable cushioning structure has a second cooperating interlocking structure and is mounted to the engine connecting end portion with the first and second interlocking structures interlocking with one another to secure the cushioning structure on the engine connecting end portion. The coupling structure couples the output shaft and driveshaft together so that powered rotation of the output shaft is transmitted to the driveshaft. The cushioning structure is positioned between the engine connecting end portion and output shaft such that the cushioning structure prevents the engine connecting end portion from abutting directly against the output shaft during relative movement of the driveshaft and output shaft towards one another.

Abstract: An electrically controlled shift and throttle system for a watercraft having multiple control stations is disclosed. The system has a number of control units having an elongated lever arm which can be moved in forward and reverse directions for shifting the transmission among forward, neutral, and reverse operating modes, as well as controlling the throttle of the engine for varying the operating speed thereof. The control units are electrically connected to a controller which also is electrically connected to a shift gear motor and throttle motor. Switches associated with each of the control units enables one of the control units to be selected as a master control unit and the nonselected control units then operate as slave units. During operation, the angular position of the master control unit lever arm is duplicated in the nonselected control units so that all control unit lever arms have the same angular orientation.

Abstract: An arrangement for utilizing a combustion sensor with an internal combustion engine. The arrangement includes a sensor mounted to the outside of an engine cylinder for communication with exhaust gasses within the cylinder via a sampling passage. A mounting structure holds the sensor proximate the sampling passage and forms a sensor chamber to receive exhaust gas therein. The sensor chamber includes a flow diverter to prevent remaining combustion particles and liquid droplets from lodging against the sensor. The chamber also includes a collection region for collecting the particles and liquid which can then be expunged through a drain outlet.

Abstract: An internal combustion engine that utilizes a control system for improving operation of the engine under a variety of conditions. The control system includes a sensor that directly senses a combustion condition in a cylinder. The output of the sensor is utilized in adjusting the air-fuel mixture delivered to other, non-sensed cylinders to optimize engine operation.

Abstract: A throttle linkage for an internal combustion engine includes a lever assembly that is configured to connect an operator-manipulated input element to an output element that controls at least a throttle of the engine. At least one stop pin is mounted on the lever assembly and is configured to engage a stationary seat when the lever assembly is in one of a full-open position and an idle position. The stop pin is axially locked with respect to the lever assembly so as to be axially nonadjustable relative to it. If the stop pin is screwed into the lever assembly, a head of the stop pin preferably faces the associated stationary seat so as to be relatively inaccessible after the throttle linkage is mounted on the engine. The head may also be covered by a cap to further hinder tampering with the stop pin. As a result of this arrangement, the operating stroke of the lever assembly is preset upon initial assembly of the lever assembly and cannot be adjusted.

Abstract: An engine system having a low EMI/RFI signature. The system comprises a two-stroke engine having a cylinder with a piston sized for reciprocal motion through the cylinder. The two-stroke engine further includes an injector deployed in communication with the combustion chamber to discharge a fuel into the combustion chamber. An electronic control unit controls the injection and ignition for the engine, and an EMI/RFI reduction system is utilized to lower the electromagnetic and radio frequency interference signature of the engine.