Abstract: An outboard motor for attachment to a hull of a marine vessel includes a lower case including a propeller shaft to rotate a propeller, and an upper case including a drive shaft to transmit a power to the propeller shaft. The lower case is selected from among different types of lower cases to be attached to the upper case, and the upper case and the lower case are connected by an intermediate structure.

Abstract: An outboard motor includes an engine, a drive shaft, and a shift shaft disposed forward of the drive shaft. The shift shaft includes a first shift shaft that extends in an upward-downward direction, a second shift shaft disposed below the first shift shaft and spaced apart from and rearward of the first shift shaft, the second shift shaft extending in the upward-downward direction, and a shift force transmission to transmit, to the second shift shaft, a shift force applied to the first shift shaft.

Abstract: An outboard motor includes an engine, a propeller shaft that rotates together with a propeller and extends in a forward-rearward direction, and a lower case that houses the propeller shaft. The lower case includes a front case and a rear case separate from the front case and positioned rearward of the front case, and the front case and the rear case are assembled to each other.

Abstract: An engine includes a crankshaft extending in a vertical direction. A drive shaft is connected to the crankshaft and coaxial with the crankshaft. A water intake passage is connected to the engine. A water pump is connected to the water intake passage. The water pump includes a pump shaft. The pump shaft is eccentrically mounted with respect to the drive shaft and parallel or substantially parallel to the drive shaft. The pump shaft rotates according to rotation of the drive shaft.

Abstract: An outboard motor includes a shift switch including a shift shaft and a rotary drive provided on an axis of the shift shaft and that rotates the shift shaft, and that switches a rotation direction of a propeller shaft. An entirety of the rotary drive is disposed below a mount, and at least a portion of the rotary drive is disposed above a lower case.

Abstract: An outboard motor includes a shaft including a second spline that upwardly extends from a housing. The second spline is meshed with a first spline disposed inside either an engine cowl or an upper housing. The second spline includes a distal end and a body. The distal end is provided on an upper end of the shaft. The body is provided below the distal end. In the second spline, a groove width in the circumferential direction at the distal end is larger than a groove width in the circumferential direction at the body.

Abstract: When a shift member is in a first position, a first clutch couples a second drive shaft to a first drive shaft. When the shift member is in the first position, a second clutch decouples a first gear from the first drive shaft. When the shift member is in the first position, a third clutch decouples a second gear from the second drive shaft.

Abstract: An outboard motor includes an engine, a propeller shaft that rotates together with a propeller and extends in a forward-rearward direction, and a lower case that houses the propeller shaft. The lower case includes a front case and a rear case separate from the front case and positioned rearward of the front case, and the front case and the rear case are assembled to each other.

Abstract: An outboard motor includes an engine, a drive shaft, and a shift shaft disposed forward of the drive shaft. The shift shaft includes a first shift shaft that extends in an upward-downward direction, a second shift shaft disposed below the first shift shaft and spaced apart from and rearward of the first shift shaft, the second shift shaft extending in the upward-downward direction, and a shift force transmission to transmit, to the second shift shaft, a shift force applied to the first shift shaft.

Abstract: When a shift member is in a first position, a first clutch couples a second drive shaft to a first drive shaft. When the shift member is in the first position, a second clutch decouples a first gear from the first drive shaft. When the shift member is in the first position, a third clutch decouples a second gear from the second drive shaft.

Abstract: An engine includes a crankshaft extending in a vertical direction. A drive shaft is connected to the crankshaft and coaxial with the crankshaft. A water intake passage is connected to the engine. A water pump is connected to the water intake passage. The water pump includes a pump shaft. The pump shaft is eccentrically mounted with respect to the drive shaft and parallel or substantially parallel to the drive shaft. The pump shaft rotates according to rotation of the drive shaft.

Abstract: Provided is a zoom lens including: positive first unit; negative second unit; aperture stop; positive third unit; positive fourth unit; and rear lens group including at least one lens unit, wherein the fourth unit includes a positive lens, and wherein an amount of movement of the fourth unit during zooming from wide angle end to telephoto end, distances between the aperture stop and the fourth unit at the wide angle end and between the aperture stop and the fourth unit at the telephoto end, focal lengths of the fourth unit and of the zoom lens at the wide angle end, a length of the zoom lens at the wide angle end, an Abbe number of material of the positive lens with respect to d-line, and a partial dispersion ratio of the material of the positive lens with respect to g-line and F-line are each appropriately set.

Abstract: An outboard motor includes a shaft including a second spline that upwardly extends from a housing. The second spline is meshed with a first spline disposed inside either an engine cowl or an upper housing. The second spline includes a distal end and a body. The distal end is provided on an upper end of the shaft. The body is provided below the distal end. In the second spline, a groove width in the circumferential direction at the distal end is larger than a groove width in the circumferential direction at the body.

Abstract: An outboard motor includes a shift switch including a shift shaft and a rotary drive provided on an axis of the shift shaft and that rotates the shift shaft, and that switches a rotation direction of a propeller shaft. An entirety of the rotary drive is disposed below a mount, and at least a portion of the rotary drive is disposed above a lower case.

Abstract: Provided is a zoom lens including: positive first unit; negative second unit; aperture stop; positive third unit; positive fourth unit; and rear lens group including at least one lens unit, wherein the fourth unit includes a positive lens, and wherein an amount of movement of the fourth unit during zooming from wide angle end to telephoto end, distances between the aperture stop and the fourth unit at the wide angle end and between the aperture stop and the fourth unit at the telephoto end, focal lengths of the fourth unit and of the zoom lens at the wide angle end, a length of the zoom lens at the wide angle end, an Abbe number of material of the positive lens with respect to d-line, and a partial dispersion ratio of the material of the positive lens with respect to g-line and F-line are each appropriately set.

Abstract: An optical system includes, in order from object side to image side, a negative front lens unit, an aperture stop, and a positive rear lens unit. The front lens unit consists of, in order from object side to image side, a negative first lens having a concave surface on image side, a negative second lens with a concave surface on image side, and a positive third lens. The rear lens unit consists of, in order from object side to image side, a positive fourth lens, and a cemented lens formed by cementing a positive lens and a negative lens together. Here, a distance on optical axis from a lens surface on object side of the first lens to a lens surface on image side of the third lens, a focal length of the third lens, and a focal length of the optical system are set to appropriate values.

Abstract: An optical system includes, in order from object side to image side, a negative front lens unit, an aperture stop, and a positive rear lens unit. The front lens unit consists of, in order from object side to image side, a negative first lens having a concave surface on image side, a negative second lens with a concave surface on image side, and a positive third lens. The rear lens unit consists of, in order from object side to image side, a positive fourth lens, and a cemented lens formed by cementing a positive lens and a negative lens together. Here, a distance on optical axis from a lens surface on object side of the first lens to a lens surface on image side of the third lens, a focal length of the third lens, and a focal length of the optical system are set to appropriate values.

Abstract: Provided is a zoom lens including a plurality of lens units, in which an interval between each pair of adjacent lens units is changed during zooming, the plurality of lens units include a lens unit BR arranged closest to image side in zoom lens, which moves in optical axis direction during focusing and a lens element A arranged adjacent to lens unit BR on object side, having refractive power of sign opposite to that of lens unit BR, in which lens element A consists of a single lens or a cemented lens, and distance between surface closest to image side of lens element A and image plane at wide angle end, distance between surface closest to image side of lens element A and surface closest to object side of lens unit BR at wide angle end, and focal length of zoom lens at wide angle end are each appropriately set.

Abstract: Provided is an optical system, including, in order from an object side to an image side: a front group having a negative refractive power; an aperture stop; and a rear group having a positive refractive power, in which: the front group consists of in order from the object side to the image side: a negative first lens (L1) having a concave surface facing the image side; a second lens (L2); and a third lens (L3); the rear group consists of, in order from the object side to the image side: a positive fourth lens (L4); and a negative cemented lens (L56), which is obtained by cementing a positive fifth lens (L5) and a negative sixth lens (L6); and a focal length f56 of the cemented lens (L56) and a focal length f of the optical system are each appropriately set.