Abstract: A method and apparatus are disclosed for controlling ignition timing during startup of a two-stroke internal combustion engine while avoiding ignition timing errors caused by engine speed fluctuations. A rotational component of the engine, such as a flywheel, bears a plurality of spaced indicator markers including a plurality of ignition triggering markers, each of which designates a position on the rotational component that is acceptable for triggering ignition in a respective cylinder of the engine. Ignition in each cylinder is triggered upon detecting the associated ignition triggering marker and without taking engine velocity into account. Ignition timing errors that could otherwise be introduced due to erroneous assumptions based on engine speed therefore are avoided.

Abstract: A control unit is provided for an internal combustion engine including an engine block comprising a plurality of cylinders operable in a homogenous combustion mode and a stratified combustion mode in response to an engine throttle position. The control unit is programmed to switch the engine cylinders to the homogenous combustion mode at a throttle position of greater than about 20% of wide open throttle. As such, the combustion mode is switched form the stratified combustion mode to the homogenous combustion mode at a higher throttle opening that more capably supports increased fuel injection quantities of homogenous combustion in the engine cylinders. Problematic conditions of conventional pontoon boat systems due to switching of engine cylinders to homogenous combustion at high RPMs and restricted throttle openings is therefore avoided.

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 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 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 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 mechanism for cleaning out an inlet grate of a water jet propulsion system. The mechanism includes an actuator and a wiper. The actuator penetrates and is supported by a through-hull housing installed in an opening in the hull. The actuator is linearly displaceable relative to the through-hull housing by manipulation of a handle or other operator input device or system. An inlet grate comprising a plurality of cantilever tines is pivotably mounted to and supported by the through-hull housing. A weed wiper is connected to the end of the actuator remote from the end that is actuated by the boat operator. When the actuator is displaced downward, the weed wiper moves downward along a linear path. At the point in the wiper displacement where the wiper bar engages the tines of the inlet grate, the downwardly displacing weed wiper causes the grate to pivot downward. During this action, the wiper slides across the grate and pushes any weeds or other debris entangled on the grate toward the ends of the tines.

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.

Abstract: The present invention, in one form, is an oiling system for an outboard engine and includes an oil tank and an oil pump located within the tank. A manifold is coupled to the oil pump, and the manifold includes a solenoid controlled valve. The solenoid controlled valve controls the flow of oil through the manifold. The manifold further includes a plurality of check valves in flow communication with the solenoid controlled valve. The check valves are in flow communication between the solenoid controlled valve and the engine cylinders. The oil system, in the one embodiment, further includes a pressure regulator in flow communication with, and downstream from, the manifold. An outlet of the pressure regulator in flow communication with the oil tank, and allows oil to flow from the manifold to the tank when pressure in the system exceeds a preselected pressure. The oil system also includes a fuel solenoid controlled valve coupled to receive oil from the manifold and to supply oil to the engine fuel system.

Abstract: An oil system for a two-stroke outboard marine engine is disclosed. The oil system includes an oil system housing having an inlet, an outlet, and an oil return. The housing includes an oil filter base to receive a replaceable oil filter thereon. The oil is routed in a closed loop that includes an oil reservoir, the inlet to the oil system housing, through the replaceable oil filter, and is then returned to the oil reservoir. Periodically, a solenoid opens the closed loop system to divert oil to the two-stroke engine, at which time a remote vent valve is activated to allow air to enter the oil reservoir to displace the dispensed oil.

Abstract: A jet-propelled boat has a hull, a mounting adapter mounted to the hull, a water jet propulsion system mounted to the mounting adapter, and seals arranged at the interface of the hull and the mounting adapter. The seals are made of a vibration isolation material such as rubber. The mounting adapter has a mounting flange which opposes a portion of the hull transom. A first seal is a generally planar layer of flexible vibration isolation material arranged between and in contact with the transom and the mounting flange. The mounting adapter also has an inlet housing which sits inside an inlet ramp formed in the hull. The inlet ramp has a recess for receiving a leading portion of the inlet housing. A second seal is a bead of flexible vibration isolation material placed in the recess. The bead sits between and in contact with the inlet ramp and the leading portion of the inlet housing.

Abstract: An exhaust pressure sensing system and method for an internal combustion engine. The system includes a pressure sensor positioned to sense exhaust pressure of an internal combustion engine. An attenuator reduces the relatively large pressure fluctuations that would otherwise impinge on the pressure sensor to provide an averaging of the exhaust backpressure to which the pressure sensor is exposed.

Abstract: An engine in which the cylinders are scavenged according to a cross scavenging technique. The engine includes one or more cylinders in each of which a piston is disposed for reciprocal motion. The engine further includes a direct fuel injection system that allows controlled input of fuel into each cylinder to promote more efficient operation of the cross scavenged engine.