Abstract: A lubrication draining and filling system provides oil passages that direct a flow of liquid oil from a bottom region of an oil sump, located within a rotatable portion of the marine propulsion system, to a discharge port which is connectable in fluid communication with a device that can sufficiently lower the pressure at the discharge port to induce the upward flow of oil from the lower portion of the oil sump within the gear case. The cavity of the oil sump within the gear case is disposed within a rotatable portion of the marine propulsion device while the discharge port is located within a stationary portion of the marine propulsion device. A transitional region comprises a space located between the stationary and rotatable portions. The oil can therefore flow from a rotatable portion, into the space, and then from the space into the stationary portion which allows it to be removed from the marine propulsion device.

Abstract: An oil temperature moderating system of an outboard motor causes cooling water to be warmed to a predefined magnitude of temperature and then conducted through a temperature responsive valve to a coolant conduit, or coolant jacket, in thermal communication with oil within an oil sump of the outboard motor. In this way, the oil within the oil sump is continuously disposed in thermal communication with cooling water that has achieved a temperature controlled by a thermostat or similar device and, as a result, is above the temperature of the water drawn from a body of water in which the outboard motor is operated. This type of system reduces the temperature of oil in the oil sump when it is greater than the cooling water flowing through the thermostat and raises the temperature of oil in the oil sump when it is cooler than water flowing through the thermostat.

Abstract: A shock absorber for a marine propulsion device is configured to provide an adapter, coupler and resilient device which can be assembled into a unit, or module, that can be inserted into a propeller. The resilient device includes two helical springs that urge the coupler into a central position with respect to the adapter and resist relative axial motion between the adapter and coupler. The shock absorber is intended to absorb the forces which occur during a shift from neutral to forward gear of the marine propulsion device.

Abstract: An exhaust system for a marine propulsion device is configured to dispose two exhaust conduits in generally concentric overlapping relation with each other in order to minimize the potential cross sectional area of a leak path in the event that a seal fails. One of the exhaust conduits extends through a transom or other surface of a marine vessel and another exhaust conduit conducts exhaust gas from an engine to the exhaust conduit extending through the surface of the marine vessel.

Abstract: A clamp member is provided with numerous lightening holes which comprise cavities and depressions formed on an inner surface of the clamp member. Bolt holes are provided through upper and lower surfaces of the clamp member and extend through the cavities. A reduced volume of the clamp member allows it to be manufactured from materials that are generally heavier than aluminum, but less susceptible to galvanic corrosion.

Abstract: A marine propulsion device is provided with a breakaway skeg having first and second attachment points. The first and second attachment points are configured to result in the second attachment points disengaging from a gear case or housing structure prior to the first attachment point. The attachment points can comprise open or closed slots and, when an open slot is used for the first attachment point, it can be provided with a first edge along which a first pin can exert a force along a preselected angle in response to an impact force on the skeg. The arrangement of attachment points allows a reaction force at the second pin to be predetermined in a way that assures the detachment of the skeg from the housing structure prior to the detachment of the housing structure from another structure, such as the boat hull, or transom.

Abstract: A deceleration profile of a jet pump propulsion system affects the manually commanded deceleration of a boat by slowing the deceleration slightly in order to enhance steering capability on plane. In response to a manual engine speed command signal that commands a desired boat speed reduction, the engine control system slows the engine deceleration according to a preselected protocol or profile, and causes the engine speed to be maintained above the engine's idle speed for a predetermined time in order to allow a greater magnitude of water to pass through the jet pump of the propulsion system so that steering control is improved.

Abstract: A support structure for a marine propulsion system utilizes a compressible member that is supported between two surfaces in a manner that prevents the compressible member from being significantly compressed. The compressible member is generally U-shaped and has two arms that have distal ends which extend away from each other to provide an appropriate sealing function without the need for significant compression of the compression member.

Abstract: A trim tab is provided in the internal portion of a nozzle of a jet propulsion system. The trim tab can be rotating about an axis to expose a surface of the trim tab to the jet stream of water passing through the nozzles of the jet propulsion system. The exposure of one of the trim tab surfaces creates a thrust vector in either the port or starboard direction which creates a corrective thrust, in a desired direction, which overcomes any manufacturing misalignments.

Abstract: A vibration dampening system incorporates an inertia mass that is disposed within a hollow portion of an impeller structure. The inertia mass is attached to one or more elastomeric members which are, in turn, attached to an inside surface of a tubular portion of the impeller structure. The annular inertia mass and its elastomeric legs are particularly designed to dampen and counteract a particular frequency at which the propulsion system vibrates when the internal combustion engine is operated at idle speed.

Abstract: The invention provides an outboard motor tilt mechanism for releasably supporting the propulsion unit in several elevated positions. A swivel bracket (16) is pivotally supported on a transom bracket (11) to provide tilting movement. A support arm (17) pivotally attached to the transom bracket (11) has an elongated slot slidably engaging a locking pin (21) fixed to the swivel bracket (16). A control handle (25) controls the tension on spring (28) to either permit or prevent engagement of the locking pin (21) with locking recesses (22, 23, 24) in the support arm (17).

Abstract: Disclosed herein is an internal combustion engine including a cooling system having a first coolant jacket portion for cooling the engine in the vicinity of the engine cylinder and a second coolant jacket portion from which the coolant is discharged. Flow of coolant from the first coolant jacket portion to the second coolant jacket portion is selectively controlled by a thermostatic valve which includes a temperature responsive element which is mounted in heat exchanging relationship with an engine block member at least partially defining a cylinder and which is operable to afford coolant flow from the first coolant jacket portion to the second coolant jacket portion when the temperature of the block member is above a predetermined level.