Abstract: A rigging apparatus is provided for an outboard motor in which an attachment member is shaped to be rigidly attached to a housing structure, or cowl, of an outboard motor, without the need for additional hardware such as clamps, brackets, or screws. The attachment member is shaped to receive a threaded sleeve in threaded association therewith so that hoses, wires, and cables can be protected within the threaded sleeve. An attachment member of the rigging apparatus is made to be asymmetrical to avoid improper assembly into an opening of the housing structure of an outboard motor.

Abstract: A cooling system for a marine propulsion device provides a water flow directing device, which is generally annular in shape, which has a water inlet extending from it. The water flow directing device is attachable to a gear case of a marine propulsion device and is configured to conduct a flow of water from a water inlet to a passage formed within the marine propulsion device and connected in fluid communication with a water pump that causes the water to flow to a cooling system of an internal combustion engine. The water flow directing device is removably attachable to a seal carrier which, in turn, is attachable to a bearing carrier disposed within an internal cavity of the gear case. A secondary inlet is provided through a surface of the gear case and in fluid communication with an internal annular passage of the water flow directing device to encourage a flow of water into the cooling system when the marine propulsion device is operating at slow speeds or is stationary in a body of water.

Abstract: A marine propulsion device is made of first and second portions which are removably attachable to each other. The second portion is the leading edge portion of the nose cone and the drive shaft housing. It can also comprise a portion of the skeg. The second portion is configured to crush more easily in response to an impact force than the first portion. This can be accomplished by making the second portion from a different material than the first portion, which can be aluminum, or by providing one or more crush boxes within the structure of the second portion to cause it to yield more quickly to an impact force and thus protect the first portion which is the more critical structure of the marine device.

Abstract: In an engine intake A/F ratio control system in an outboard engine system, a secondary air passage (P) for supplying secondary air for regulating the A/F ratio of an air-fuel mixture is connected to a carburetor (33) in an intake system of an engine (E), and a duty control valve (68) is connected to the secondary air passage (P). A duty control unit (92) is connected to the duty control valve (68) for controlling the duty ratio of a pulse applied to a coil (76) of the duty control valve (68), and an LAF sensor (94) is mounted to an exhaust system for detecting an A/F ratio of an exhaust gas to input a detection signal proportional to the A/F ratio of the exhaust gas to the duty control unit (92).

Abstract: An outboard drive unit for a watercraft to allow propulsion of the watercraft in mud and water. The drive unit has a reduction gear assembly mounted between a motor and a propeller assembly, thereby allowing an engine of given capacity to turn a propeller with increase pitch and surface plane area. A propeller shaft is oriented at an obtuse angle in relation to an input shaft extending from the motor to allow the watercraft to accelerate easier, especially in mud conditions, while protecting the propeller from impact with grass and under water obstructions.

Abstract: Readout devices and controls are provided that alert the user to unusual propeller slip conditions. Embodiments of the invention incorporate some signal processing to account for a progressively greater slip at lower watercraft speeds. Thus, the invention provides simple information that tells the user if a boat propeller combination is being operated suboptimally, without requiring the knowledge and use of multiple slip figures for differing boat speeds. The invention allows greater economy of operation, automatic anticavitation control and can alert the watercraft operator to unusual conditions such as anchor down, propeller up other situations that affect propeller loading.

Abstract: An outboard motor has an engine, a propeller drivable by the engine, and a drive shaft for transmitting a driving force from the engine to the propeller. A casing assembly supports the engine and rotatably supports and accommodates the drive shaft. A cover structure defines at least part of an engine space accommodating therein the engine. The cover structure has a resin cover body comprised of at least first and second cover members detachably connected to one another, and a frame assembly integrally connected to an inner surface of the first cover member for reinforcement threof. The first cover member has an opened flange receiving a seal of the second cover member. The frame assembly extends along a contour of the opened flange.

Abstract: An outboard drive unit for a watercraft to allow propulsion of the watercraft in mud and water. The drive unit has a reduction gear assembly mounted between a motor and a propeller assembly, thereby allowing an engine of given capacity to turn a propeller with increase pitch and surface plane area. A propeller shaft is oriented at an obtuse angle in relation to an input shaft extending from the motor to allow the watercraft to accelerate easier, especially in mud conditions, while protecting the propeller from impact with grass and under water obstructions.

Abstract: The present invention provides a stern drive propulsion system that includes an internal combustion engine having a flywheel and a watertight housing that sealingly encloses the flywheel relative to the surrounding environment. The housing may support a starter coupled to the flywheel and extending toward the transom of a boat. A starter seal is provided to seal corresponding interface surfaces of the starter and the flywheel housing.

Abstract: A marine propulsion housing arrangement includes an improved construction for inhibiting an influx of water into the housing and for protecting the components thereof. A marine outboard drive comprises a drive unit and at least a swivel bracket that supports the drive unit for pivotal movement with a steering shaft. At least one mount assembly is provided for unifying the drive unit and the steering shaft. The mount assembly includes at least one mount members affixed to the drive unit and a hub member united with the mount member. The hub member is connected to both the drive unit and the steering shaft so as to unify them. A mount cover generally covers both of the mount member and the hub member.

Abstract: An outboard motor has an under cover forming a lower part of an engine room in which an engine is installed. The under cover has a pair of right and left cover members detachably connected together along opposing vertical edges thereof; an opening formed in at least one of the cover members for allowing access to the engine. The opening is vertically spaced from an upper edge of the under cover and extends contiguously from the vertical edge of the at least one cover member. A lid made of elastic material is attached to an outer surface of the under cover so as to close the opening of the under cover, the lid being elastically deformable to open and close the opening.

Abstract: A process for forming an improved anodizing film on the surface of an aluminum alloy material. The film is impregnated with an amorphous substance which fills pores formed in the film during its growth. If the film has a flaw reaching the aluminum alloy material, the amorphous substance and aluminum form a layer of passivity which restrains the corrosion of the aluminum alloy material.

Abstract: A cowling assembly for an outboard motor includes an improved construction that can supply relatively cool air containing little water to the induction device and can also supply air to cool engine components without reducing the charging efficiency. The outboard motor has an engine that includes an air induction device and is enclosed within the cowling. The cowling assembly defines a closed cavity in which the engine is contained and has an air intake system. An air intake duct structure introduces air into the cavity. The intake duct structure includes a plurality of relatively narrow connection passages and has an expansion chamber portion disposed on the downstream side of the passages. Intake noise is reduced by this construction. In one preferred form, the cowling assembly additionally has a second intake system. One or more connection passages communicate with the first air intake system and the second air intake system.

Abstract: A stern drive system having an outdrive generally disposed downstream relative to water flow aft a transom of the boat is configured to be rotated about a generally horizontal axis to impart a desired trim or tilt to the drive system. A tilt-trim subsystem assembly is affixed to the outdrive and has one respective end thereof configured to pivotally receive an anchor pin supported by the outdrive. The assembly includes at least one cylinder having one end thereof connected to another anchor pin so that when the cylinder is actuated by a circuit therein the outdrive and the tilt subsystem assembly are rotated about the generally horizontal axis during tilt maneuvers. A housing is provided to shield the tilt assembly and configured within the footprint of the outdrive to avoid resistance to water flow. Additionally, the housing may be configured to visually shield the tilt assembly from observers.

Abstract: An outboard engine with a grip recess formed on a part of an engine cover surface. The grip recess can be used as a handle by inserting an operator's hand thereinto. The outboard engine may be lifted up by using the grip recess as a handle during a tilt-up operation. This allows the outboard engine to be rotated upwardly easily about a tilt axis.

Abstract: The present invention, in one form, is a skeg having an airfoil shape which facilitates maintaining engine control even at high speed but does not adversely affect engine performance. In one embodiment, the skeg includes a fore end, an aft end, and opposing sidewalls extending from the fore end and the aft end. One sidewall includes a camber, or curved surface, and the outer surface of the other sidewall is flat, or planar.

Abstract: Stern drive assembly configured for utilization in an inboard/outboard power plant for a boat. The stern drive assembly includes a central rigid core that is configured at an upper portion to be coupled to the stern of a carrying boat. A lower portion of the core is designed to accept a boat-moving force generated by a water propulsion unit that is coupled thereto. A thin-walled housing is configured to be secured about a predominance of the centrally located rigid core. The housing has an outer surface that establishes an exterior of the stern drive assembly and an inner surface directed generally toward the central rigid core. A portion of an exterior surface of the central rigid core is configured to cooperate with a corresponding portion of the inner surface of the thin-walled housing. These two portions, when in cooperative orientation one with the other, form a functional feature for the stern drive assembly.

Abstract: In an engine intake A/F ratio control system in an outboard engine system, a secondary air passage (P) for supplying secondary air for regulating the A/F ratio of an air-fuel mixture is connected to a carburetor (33) in an intake system of an engine (E), and a duty control valve (68) is connected to the secondary air passage (P). A duty control unit (92) is connected to the duty control valve (68) for controlling the duty ratio of a pulse applied to a coil (76) of the duty control valve (68), and an LAF sensor (94) is mounted to an exhaust system for detecting an A/F ratio of an exhaust gas to input a detection signal proportional to the A/F ratio of the exhaust gas to the duty control unit (92).

Abstract: An outboard motor includes a power head, driveshaft housing and lower unit, and employs a cooling system to cool the driveshaft housing. Portions of the driveshaft housing experience substantial heat transfer from the exhaust gases that pass through the driveshaft housing. The driveshaft housing cooling system cools the heated portions of the driveshaft housing. The cooling system includes delivery pipes adapted to deliver water to the outer surface of each side of the driveshaft housing. The water is distributed to the housing outer surface in a manner to establish a substantially even flow across the surface so that heat is dissipated from the housing in order to prevent the housing from reaching very high temperatures.

Abstract: A propulsion system for a boat has a powerhead or a motor with an exhaust port for exhaust gases. The exhaust gases are exhausted through the propeller hub via an exhaust housing. The exhaust housing is a walled enclosure having an inlet, an internal volume in flow communication with the inlet, and an outlet in flow communication with the internal volume. The exhaust housing further includes hollow structures for dividing a portion of the internal volume into a plurality of flow channels which extend in side-by-side relationship. The transverse dimensions of each flow channel is substantially less than the transverse dimensions of the walled enclosure. The result is that standing waves are shifted to a higher frequency range. The hollow dividing structures have internal volumes which communicate with space external to the exhaust housing via openings in the walled enclosure, which allow the admission of a cooling medium.

Abstract: An outboard motor has a first case member and a second case member connected to the first case member to form an enclosure having an inner space in which is mounted an engine. The first case member has an air intake hole for taking air into the inner space and a vent hole for exhausting the air after it circulates in the inner space to cool the interior of the inner space. An alternator is disposed in the inner space of the enclosure and has a hollow casing, air passage holes formed in the hollow casing, and cooling fans for drawing air from the air passage holes into the hollow casing to cool the alternator. A cover member is disposed in the inner space of the enclosure and covers at least a portion of the alternator.

Abstract: An exhaust system for an outboard motor includes an improved construction that can reduce cost for providing an expansion chamber of an idle exhaust discharge. The outboard motor includes an engine and a protective cowling that surrounds the engine. The protective cowling includes a top and bottom cowling members. The expansion chamber of the idle exhaust route is defined by at least a bottom surface of the bottom cowling member and a separable member.

Abstract: A marine outboard drive, such as an outboard motor, includes both a splash plate and an anti-splash device. The anti-splash device includes a second splash plate that is provided on a lower mount, which couples together a swivel bracket and a drive housing. The second splash plate extends generally forwardly of the swivel bracket just under a lower portion of a clamp bracket that supports the swivel bracket. The anti-splash device preferably also includes a guide that is provided above the conventional splash plate for directing splashed water rearwardly so that the water is guided away from a mount cover that covers the lower mount. These features of the anti-splash device are particularly useful when the outboard drive is used with a pontoon boat.

Abstract: An outboard engine system includes a casing having a driving-force transmitting device provided therein, and an engine for transmitting power through the driving-force transmitting device to a propeller. The casing and the engine are carried on a hull for tilting-up movement. An engine cover made of a synthetic resin covers at least an upper portion of the engine, and an undercover comprises a pair of cover halves made of a synthetic resin and connected to each other to cover at least a lower portion of the engine from opposite sides. The undercover is detachably connected at its upper end to a lower end of the engine cover and fixed to an upper portion of the casing. In such outboard engine system, the undercover is detachably fixed at its upper portion to a body of the engine. Thus, the undercover can be supported so as to give an impression that the engine cover and the undercover are rigid during a tilting-up operation.

Abstract: An outboard motor includes a propulsion unit having a power head which includes an internal combustion engine, a lower unit including a drive shaft housing fixed to the engine and a propeller shaft joined by the lower unit driven by the engine and having thereon a propeller. A cowling extends over the engine downwardly to the drive shaft housing defining an enclosed space containing the engine. An opening is provided to the enclosed space proximate the juncture between the cowling and the drive shaft housing. A plurality of electrical cables enter the enclosed space through the opening. A sealed housing is mounted to a side of the engine and contains a plurality of electrical devises for operating the engine. The cables connect to preselected devices by means of water-tight connections on the housing.

Abstract: A housing for an outdrive is installed with a replaceable tower support for a ball bearing race through which the drive shaft rotates. When the bearing race becomes worn, rather than replacing the entire housing and installing a new bearing race, only the tower support and worn bearing race is removed and replaced, which represents a considerable cost saving.

Abstract: A housing for a propulsion system, such as for a plurality of disks, is provided as well as a system and a method for using the same. The housing is shaped to provide a streamlined motion through a fluid, such as air or water. Openings in the housing allow the fluid to flow through the propulsion system. The housing may be attached to a shaft in a motor or engine to provide a drive for the propulsion system contained therein.

Abstract: Cooling apparatus for the stern drive unit of a marine inboard-outboard drive system, the cooling apparatus being of the kind making use of the ram effect and having an intake tube carried on the stern drive unit with its intake end in the water. The tube has an intake port held below the water surface for accepting water by the ram effect while the boat is moving forward. The water is carried by the tube to a system for delivering water from the intake tube to the stern drive unit for cooling it. According to the invention the bottom of the intake tube is closed and the intake port is formed closely adjacent to the bottom of the tube in a selected part of its wall facing forwardly when the boat is in forward motion.

Abstract: A driveshaft housing for an outboard motor includes an improved construction. The outboard motor comprises a power head containing an engine, the driveshaft housing depending from the power head and containing a driveshaft, and a lower unit depending from the driveshaft housing and supporting a propulsion device. The engine includes an exhaust system having an exhaust conduit at least in part extending through the driveshaft housing. The driveshaft housing has a rib extending from one lateral side wall portion to another lateral wall portion between the driveshaft and the exhaust conduit. The stiffening rib strengthen the rigidity of the lateral side walls of the driveshaft housing, and thereby inhibits inward and outward movement of the lateral side walls, particularly in a region where the walls define a portion of an expansion chamber of the exhaust system within the driveshaft housing.

Abstract: An outboard motor is provided with an engine covered by an engine cover composed of a plurality of cover elements and formed with a port member having an cable insertion port through which operation cables are guided inside an outboard motor and an operation cable mounting structure is formed to the outboard motor, which comprises: a port member being arranged so as to straddle a plurality of the cover elements of the engine cover and composed of a first port member half provided to one of the cover elements and a second port member half provided to another one of the cover elements, the port member halves having openings opposed to each other so that when the port member halves are mated and joined together, the port member having a cable insertion port as a unit member having an opening; a grommet closing the opening of the cable insertion port; a partition wall section disposed in one of the first and second port member halves so as to divide the opening of the cable insertion port; and a boss member provi

Abstract: In an outboard motor, an engine is covered by an engine cover unit, and the engine cover unit comprises a lower cover section covering a surrounding of a lower portion of an engine in a usable state of an outboard motor arranged vertically, an upper cover section covering a surrounding of an upper portion of the engine, the upper cover section being mounted to be detachable to the lower cover section so as to provide an engine cover when mounted, and a height adjusting device provided for an inside surface of the lower cover section and adapted to adjust a height of the engine cover.

Abstract: In an outboard engine, a support member for supporting a drive shaft and an exhaust pipe within an extension case can be cooled by outside water pumped by utilizing the exhaust pressure from the engine. The inside of the extension case is divided, by the support member for supporting the drive shaft and the exhaust pipe, into an upper chamber communicating with the open air, and a lower chamber into which outside water is introduced, so that the exhaust gas from the exhaust pipe is discharged into the lower chamber. Both the upper and lower chambers are in communication with each other through a communication pipe. Thus, during operation of the engine, the support member and the depending members are cooled by the outside water forced up from the lower chamber through the communication pipe into the upper chamber.

Abstract: In an outboard motor, a simple drain structure is provided which can drain the water that has entered the engine compartment while effectively preventing water from entering the engine compartment through the drain structure itself. A drain passage is formed in a peripheral portion of an engine mount member which, together with a part of an engine cover, constitutes a bottom of the engine compartment. A reed valve unit made of a resilient material and having a base portion and a valve portion is fittingly received by the side wall defining the drain passage of the mount member so that the valve portion normally closes the opening of the drain passage due to its own resiliency and bend to drain water when water accumulates in the drain passage.

Abstract: A marine outboard drive that is equipped with integrated splash plates and a baffle plate that prevent water splash-up along the drive shaft housing. The baffle plate protrudes from the drive shaft housing to interact with plates on the lower bracket to create a labyrinth effect. The labyrinth created by the splash and baffle plates impedes the path of any water impinging upon the lower bracket and the drive shaft housing. This minimizes the amount of water travelling up the drive shaft housing. A splash plate may also be included on the lower bracket to minimize water flow above the lower bracket.

Abstract: An outboard motor to be mounted to a hull comprises an engine holder connected to the hull, an engine mounted on the engine holder in a perpendicular fashion in which a crank shaft of the engine extends vertically, an oil pan mounted to a lower portion of the engine holder, and an oil pump for supplying an oil stored in the oil pan to the engine, in which the engine including a crank case, a cylinder block and a cylinder head, which are all secured to the engine holder by fastening bolts for improving the rigidity of a mounted engine and that of an assembled outboard motor and simplifying the structure thereof.

Abstract: An outboard motor generally comprises an engine holder to be mounted to a hull, an engine disposed in an upper portion of the engine holder in a mounted state thereof, an oil pan disposed in a lower portion of the engine holder, and a drive-shaft housing disposed below the oil pan and adapted to house a drive shaft of the engine, in which an exhaust gas from the engine is guided to the drive-shaft housing through an exhaust gas passage and the exhaust gas in the drive-shaft housing is discharged outward through an exhaust release passage connected to the drive-shaft housing at a time of low-speed revolution of the engine such as idling operation.

Abstract: A lower unit for a marine propulsion system has a flow disrupter positioned along the side wall of the vertical strut above the torpedo gearcase. The strut has a high pressure side and low pressure side which results from the strut being positioned at an angle with respect to the direction of boat travel in order to compensate for steering torque. The flow disrupter is positioned on the low pressure side of the strut, and promotes the separation of water passing over the vertical strut in a controlled manner, thereby reducing steering jerks during acceleration due to dramatic hydrodynamic flow changes. The flow disrupter consists of a series of steps or textured areas positioned along the aft section of the vertical strut. In a preferred embodiment, each of the steps contains a vent passage permitting exhaust to exit the strut through the steps to further promote controlled separation of water passing over the strut.

Abstract: A outboard motor mounting system where there is a device for connecting the steering shaft to the drive shaft housing and lower unit comprised of an attaching bracket at least partially encircling and engaging the drive shaft housing and lower unit. There is also a splash plate to deflect water splashed by the driveshaft housing and lower unit that is formed integrally with the attaching bracket comprising a surface extending forwardly and laterally from the main body of the attaching bracket.

Abstract: A protection bar for the front edge of the lower housing portion of a drive housing of the boat motor comprises an elongate bar with a grooved rear edge friction fit on the front edge of the housing and the front edge of the scag plate. The top end of the bar is bolted to the flange coupling between the upper and lower housing portions. The lower end is bolted to the scag plate by a pair of side mounting plates and a cross bolt. The bar follows the shape of the front edges of the housing and the scag plate. The protection bar absorbs impacts to prevent damage to the cast housing portions.

Abstract: A twin propeller marine propulsion unit for a watercraft. A vertical drive shaft operably connected to the engine is journaled for rotation in a lower gear case and carries a beveled pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo-shaped section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch, is moved in one direction to operably connect a first of the bevel gears with the inner propeller shaft to thereby drive the rear propeller. When the engine speed reaches a pre-selected elevated value, a hydraulically operated multi-disc clutch is actuated to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: Sacrificial anode arrangements for marine propulsion units wherein the sacrificial anode is juxtaposed to the trim tab and is detachably connected to the lower unit housing by fastening means which can be removed from the upper surface thereof. In one embodiment, the trim tab is detachably connected to the sacrificial anode is connected to the outer housing portion through the sacrificial anode.

Abstract: The present invention is a skeg cover which may be fitted onto either a damaged skeg or a new skeg to prevent shaft, gear, or propeller damage. The present invention is constructed such that it is inexpensive and may be quickly and easily installed by a boat owner.

Abstract: An adapter plate to attach a four cycle internal combustion verticle shaft engine to an outboard motor lower drive unit creating a four cycle internal combustion engine outboard motor for powering small boats and crafts through the water.

Abstract: An outboard motor incorporating a unitary mounting assembly for resiliently connecting the steering shaft to the driveshaft housing. The mounting assembly also closes an upper portion of the driveshaft housing and has an opening that passes a water tube for supplying cooling water to the engine of the outboard motor.

Abstract: A nose cone attachment for an outboard motor propeller gearcase has a molded polymer housing shaped to fit over the front and sides of an outboard propeller gearcase and has an aerodynamic nosepiece shape on the front thereof with a plurality of water inlets thereon. The molded polymer housing has open water channels or plenums thereinside which form wide passageways with the gearcase housing sides when the nose cone attachment is attached over the gearcase housing. The open water channels are positioned to fit over the gearcase water inlets. The housing is adhesively attached but may also have a plurality of screw openings formed in the side thereof and positioned for attaching screws therethrough to attach the nose cone to a gearcase outboard motor prop.

Abstract: A multi-cylinder engine structure includes a multi-cylinder engine body having a plurality of cylinders vertically arranged therein. A fuel feed system has a fuel pump connected to a plurality of carburetors disposed in a vertical arrangement sideways of the engine body in independent correspondence to the cylinders. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically. An outboard engine includes a case tiltably mounted at a stern. A multi-cylinder engine body is contained in the case. A fuel feed system supplies a fuel to a plurality of carburetors disposed in correspondence with the cylinders. A fuel filter is also provided. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically and above the fuel filter in a tilted-down state of the case.

Abstract: Two embodiments of carrying handles that can be permanently connected to an outboard motor for carrying the outboard motor when not in use. In each embodiment the carrying handle is connected so that it extends in a generally vertical direction in normal condition of the outboard motor and which can be grasped by a user for carrying of the outboard motor at the user's side, with the user's wrist in a normal condition. The carrying handle is associated with a latching bracket that latches the lower end of the handle to the clamping bracket for the carrying operation.

Abstract: Disclosed herein is an outboard motor including an engine block assembly comprising an engine block, a crankshaft rotatably supported by the engine block and including an upper part above the engine block, a flywheel fixed on the upper part of the crankshaft, a recoil starter above the flywheel, a crankshaft timing gear fixed on the upper part of the crankshaft, a camshaft rotatably supported by the engine block and including an upper part above the engine block, a camshaft timing gear fixed to the upper part of the camshaft and located above the engine block, a timing belt extending between and around the crankshaft timing gear and the camshaft timing gear, and a one-piece cover mounted on the engine block and enclosing the flywheel, the recoil starter, the camshaft timing gear, and the timing belt, and a cowling enclosing the engine block assembly.

Abstract: Disclosed herein is a one piece drive shaft housing comprising a casting including an outer surface having an upper end surface, a lower end surface, and an endless side surface extending between the upper and lower end surfaces, an internal cavity extending between the upper and lower end surfaces and adapted to receive a drive shaft and a clutch operated linkage, an internal exhaust gas passage extending between the upper and lower end surfaces and located in spaced relation to the cavity, an internal coolant supply passage extending between the upper and lower end surfaces, an internal idle exhaust passage including a series of expansion chambers and extending between the upper end surface and the endless side surface, and an internal coolant drainage passage extending between the upper and lower end surfaces in heat exchanging relation to the exhaust gas passage.

Abstract: The present invention relates to an aquatic propulsion system of modular construction. The system includes an electric motor and a gearbox that are removables as a unit. The electric motor and gearbox are housed in a two piece enclosure. A retaining ring threadably engages one of said pieces while engaging a flange on the other piece to secure the two pieces together. Optional struts are attached to the retaining ring that support a shroud around the system's propeller.