Abstract: A marine drive shift mechanism includes a shift ring (200) having a chamfer zone (204) along an arcuate portion of its outer circumference facilitating ease of shifting. A stepped camming surface (222) provides step function shifting movement. Neutral positioning notches (238, 240) are provided on the clutch sleeve (18) to improve clutch sleeve (18) placement when the shift mechanism is in neutral.

Abstract: A marine drive (10, 310) has two counter-rotating propellers (12 and 14, 312 and 314). Inner and outer concentric counter-rotating propeller shafts (40 and 42, 340 and 338) are supported by a spool (38, 336) in the lower horizontal bore (28, 328). Passages are provided in the housing for communicating lubrication and/or exhaust with the horizontal bore. Locking structure (50, 404) holds the driven gears and bearings in place in the lower horizontal bore.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). A planing plate (230) extends rearwardly from the drive housing (20) above the propellers (12 and 14) and pushes down on the surface of the water during initial boat acceleration to in turn lower the bow and aid in getting the boat up on plane. Right and left inclined splash plates (240 and 242) along the sides of the housing (20) extend from the torpedo portion (188) rearwardly and upwardly at an incline and meet the planing plate (230).

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The drive has a vertical X-dimension (254) in the range of about 13 inches to 19 inches in combination with a shaft-spacing dimension (258) in the range of about 8 inches to 15 inches in combination with a surfacing dimension .gtoreq. zero. In one embodiment, the shaft-spacing dimension is 13.5 inches, the vertical X-dimension is 16 inches, and the surfacing dimension is 2 inches.

Abstract: A surfacing marine drive has a drive housing (20) with a fore exhaust passage (230) forward of the vertical bore (26) housing the driveshaft (36), right and left exhaust passages (232 and 234) extending rearwardly from the fore exhaust passage (230) on opposite right and left sides of the vertical bore (26), and an aft exhaust passage (236) extending rearwardly from the right and left exhaust passages (232 and 234) and aft of the vertical bore (26) and discharging exhaust into dual counterrotating surface operating propellers (12 and 14).

Abstract: A marine drive (10) has a water inlet (234) on the side of the skeg (194). One or more turning vanes (261, 289) receive incoming water flow and turn and direct same forwardly and upwardly within the skeg to a torpedo nose passage (198). A flow divider (284, 285) separates incoming water flow entering the water inlet opening into upper and lower water streams each initially flowing along a first path horizontally rearwardly and then along a second curved path and then merging along a third path upwardly and forwardly in an internal water passage (196) in the skeg. Water inlet plate structure maintains desired water intake flow volume.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The lower horizontal torpedo portion (188) of the housing (20) has an upper zone (276) with outer surface profiles (11T-17T) along horizontal cross-sections defining wedges with sharp leading tips (11LT-17LT) forming a sharp leading edge (278) for slicing through the water, the sharp leading tips (11LT-17LT) defining the sharp leading edge (278) defining a first line extending downwardly and rearwardly at a first angle (280) relative to vertical. The torpedo portion (188) has a lower zone (270) with outer surface profiles (1B-10B) along horizontal cross-sections defining wedges with sharp leading tips (1LT-10LT) defining a second line (272) extending downwardly and rearwardly at a second angle (274) relative to vertical.

Abstract: A marine drive (10, 310) has two counter-rotating propellers (12 and 14, 312 and 314). Inner and outer concentric counter-rotating propeller shafts (40 and 42, 340 and 338) are supported by a spool (38, 336) in the lower horizontal bore (28, 328). Passages are provided in the housing for communicating lubrication and/or exhaust with the horizontal bore. Locking structure (50, 404) holds the driven gears and bearings in place in the lower horizontal bore.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The upper end (302) of the leading edge (288) of the skeg (194) is spaced forwardly of the lower end (310) of the trailing edge (306) of the skeg (194) by a horizontal distance greater than the horizontal length of the torpedo (188), for full rudder control. The skeg (194) has a first zone (318) with outer surface profiles (12P-15P) which are continuous and define continuous skeg sidewalls (320, 322) therealong. The skeg (194) has a second zone (324) above the first zone (318) and with outer surface profiles (9P-11P) along horizontal cross-sections, which profiles are discontinuous and define skeg sidewalls with openings (192, 193) therein. The horizontal cross-sections along the second zone (324) have discontinuous gaps (332, 333, 336) therein defining a cored passage (196) within the skeg (194) communicating with the openings (192, 193) in the sidewalls (320, 322).

Abstract: A marine drive is provided with a large volume anode, about 30 cubic inches, for galvanic protection. The anode (230) is a brick-like block member tapered along each of its height, width and length dimensions. The drive housing has an anode-mounting section (232) extending rearwardly therefrom and has a downwardly opening cavity (234) of substantially the same shape and volume as the anode, and receiving the anode in nested flush relation.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12, 14). Inner and outer concentric counter-rotating propeller shafts (40, 42) are supported by a spool assembly (38) locked and retained against rotation and against axial movement in the lower horizontal bore (28) in the torpedo (34) of the drive housing (26) by axially spaced left and right hand threads (44 and 46). A thrust bearing assembly (98) transfers thrust from the outer propeller shaft to the inner propeller shaft during rotation of the propeller shafts in opposite axial direction and is axially located between fore and aft driven gears (76 and 78). Propeller shaft sealing and bearing structure, and propeller self-centering mounting structure is provided.

Abstract: An apparatus and method for providing improved oil circulation in a marine propulsion system. A supply passage is formed in the gearcase, having its inlet in communication with a space located forwardly of the lower face of the driven gear located in the propeller shaft cavity. The supply passage communicates oil to a drive shaft housing supply passage, and communication between the drive shaft housing supply passage and the upper cavity formed in the drive shaft housing, within which are disposed the lower and upper gears and the input gear, is cut off. Oil flowing through the drive shaft housing supply passage is routed to the universal joint bearings, and temperature of oil at the universal joint bearings is significantly reduced.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). An upper adaptor spool (48) has a lower threaded outer portion (50) mating with a threaded portion (46) of the vertical bore (26) of the drive housing (20) and supporting the upper gear (42) for rotation about the driveshaft (36) and supporting the driveshaft (36) for rotation within the adaptor spool (48). Vertical bore structure enables assembly from above of the majority of the vertical drive train components into a one-piece unitary integrally cast housing. The vertical distance between the adaptor spool (48) and the lower bearing (118) supporting the vertical driveshaft (36) is about equal to propeller radius. The lower concentric counter-rotating propeller shafts (156, 158) are spaced from the upper input shaft (28) by a distance along the driveshaft (36) in the range of about 9 to 15 inches.

Abstract: A marine stern drive unit (1) includes a fluid passage disposed within a drive shaft housing (11) of cast construction. The fluid passage has a discharge outlet (23) which is connected to the lower inlet end (41) of a generally centrally disposed vertical water cavity (24) cored into the drive shaft housing casting. The connection is very simple between the outlet and inlet. In addition, the vertical water cavity (24) in the drive shaft housing casting (19) is connected to a horizontal water pocket (59) therein through an angular connector passage (67) which is formed in a manner so as to require drilling through only a single wall remote from the shift pocket. The angularities involved reduce the sharpness of fluid flow turns.

Abstract: A transparent container (20, 48) is mounted to the inner transom wall (2) of a boat (3) and is connected to the oil passages in a stern drive unit (1). The container is provided with a removable cap (25) having a one-way valve (27) of the Vernay type therein. The valve prevents outward leakage of lubricant fluid from the container, but permits inward passage of air so that, during engine and drive unit cooling, lubricant can be sucked back into the system through the drive housings. The cap may be provided with a lubricant level warning device (41-43; 45-47) which extends downwardly into the container. In another embodiment, the warning device is spaced from the cap and extends upwardly into the container. In another embodiment, the container may be provided with a spring loaded diaphragm (53) which is movably responsive to the lubricant pressure within the stern drive unit.

Abstract: A fluid flow tube (9) is provided which extends from the lower portion of the engine oil pan (7) to a point on the boat transom (2) below the pan. The upper end portion of the tube is connected through a control valve (10) which communicates with the pan interior. The lower or discharge tube end portion is connected through a fitting (11) extending through the transom. A removable plug (17) is associated with the fitting and, when removed, permits oil to drain out through the transom and into an oil collection receptacle when the control valve is open.

Abstract: A sacrificial anode (19, 47, 55, 61) is disposed in association with the trim cylinder unit (12) of a marine propulsion device and is positioned in the previously unused area between the aft cylinder (13) end and the rodeye (16) or the like on the piston rod (15) end. More specifically, the anode is in the form of an elongated generally cylindrical member of a diameter approximating that of the trim cylinder to provide improved mass characteristics, and is deeply grooved (21) to thus provide ribs (22) which enhance the working surface area. The anode may be attached to an extended pilot member (23, 45) which is suitably secured within the aft end of the trim cylinder. It is contemplated that a cover (35) may be utilized in conjunction with the anode to improve the aesthetic appearance of the affected area, while permitting water flow through the anode. In one embodiment, a unitary anode (19) is provided with a radial slot (33), which permits the anode to be positioned over the trim cylinder rod (15).

Abstract: A marine stern drive unit (1) includes an assemblage of a propeller-carrying drive shaft housing (10), a bell housing (9) and gimbal housing (8). Mating flow-through passages (21, 23) are disposed in the drive shaft housing and bell housing, and a dual control valve system (30, 31) joins the passages at their juncture. The valve system is arranged to be open when the two housings are assembled, but closes automatically when the housings are disassembled to retain lubricant in the separate housing assembles when the latter are separated for servicing. The valve system includes a valve (31) in one of the passages (23) which is constructed to be snapped together and to be held firmly within the passage, but manually and quickly releasable therefrom when desired. The fluid passage (23, 26) in the bell housing communicates to the gimbal housing which has a sealed fitting (60) and a lubricant carrying portion (65) passing through the usual gimbal mounting hole (14) of the boat transom (2).

Abstract: A marine propulsion unit (1) is provided wherein the main drive shaft (42) includes an integrally formed annular portion (46) of enlarged diameter at the location of a previously utilized lower groove and keepers (38, 37). The enlarged diameter portion increases the mass and strength of the shaft at a position subject to substantial torque forces, thus substantially eliminating problems of shaft fracture or breakage. In addition, the enlarged diameter portion is formed in the shape of a thrust collar so that the shaft can be accommodated by the previous known shaft mounting elements without redesign of the latter.

Abstract: A marine drive (2) having a lower gearcase (4) with a torpedo housing (10) having an internal lubricant-containing cavity (26) has a removable drain plug (50) and drain plug hole (52) at a location away from the exterior hydrodynamic surface (46) of the torpedo housing along which water flows, to prevent cavitation burns on the torpedo housing and the propeller (24), and to aid in eliminating propeller ventilation.