A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device at a discharge angle relative to a vertical axis. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device at a discharge angle relative to a vertical axis. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device along a discharge trajectory parallel to a plane that bisects the device into a port side and a starboard side. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device along a discharge trajectory parallel to a plane that bisects the device into a port side and a starboard side. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

An end cap for guiding an exhaust gas flow of a boat engine. The end cap is configured to be attached onto a propeller nut of the boat engine. The end cap including: a base body having a bottom surface, a lateral surface and a tip, the tip and the bottom surface being spaced apart from each other in a longitudinal direction of the base body. The lateral surface extends from the bottom surface and converges in the tip. The bottom surface having a recess for receiving the propeller nut; and at least one exhaust gas-guiding structure extends helically along the lateral surface.

An end cap for guiding an exhaust gas flow of a boat engine. The end cap is configured to be attached onto a propeller nut of the boat engine. The end cap including: a base body having a bottom surface, a lateral surface and a tip, the tip and the bottom surface being spaced apart from each other in a longitudinal direction of the base body. The lateral surface extends from the bottom surface and converges in the tip. The bottom surface having a recess for receiving the propeller nut; and at least one exhaust gas-guiding structure extends helically along the lateral surface.

A marine drive has a primary exhaust outlet on its lower gearcase that discharges a primary flow of exhaust gas from the engine to seawater in which the marine drive is situated. A secondary exhaust outlet is located on the marine drive above the primary exhaust outlet and discharges a secondary flow of exhaust gas from the engine to atmosphere around the marine drive at least when the engine is operated at an idle speed. A tertiary exhaust outlet is located on the marine drive between the primary and secondary exhaust outlets, and discharges a tertiary flow of exhaust gas from the engine to the seawater or to the atmosphere depending upon a current location of the tertiary exhaust outlet with respect to the seawater. A muffler is configured to reduce noise emanating from the tertiary exhaust outlet.

A marine drive has a primary exhaust outlet on its lower gearcase that discharges a primary flow of exhaust gas from the engine to seawater in which the marine drive is situated. A secondary exhaust outlet is located on the marine drive above the primary exhaust outlet and discharges a secondary flow of exhaust gas from the engine to atmosphere around the marine drive at least when the engine is operated at an idle speed. A tertiary exhaust outlet is located on the marine drive between the primary and secondary exhaust outlets, and discharges a tertiary flow of exhaust gas from the engine to the seawater or to the atmosphere depending upon a current location of the tertiary exhaust outlet with respect to the seawater. A muffler is configured to reduce noise emanating from the tertiary exhaust outlet.

A method is for making a marine drive for propelling a marine vessel in water. The method includes providing a gearcase; installing a propeller shaft assembly that extends forwardly from the gearcase; coupling front and rear propellers to the propeller shaft assembly, forwardly of the gearcase, such that rotation of the propeller shaft assembly causes rotation of the front and rear propellers, respectively, which thereby propels the marine vessel in the water; and reducing deleterious effects of cavitation on the gearcase by the combination of forming the gearcase with a wide trailing end portion, in particular to maintain pressure alongside the gearcase, and configuring the front and rear propellers so that the front propeller absorbs more torque/thrust load than the rear propeller during said rotation.

A method is for making a marine drive for propelling a marine vessel in water. The method includes providing a gearcase; installing a propeller shaft assembly that extends forwardly from the gearcase; coupling front and rear propellers to the propeller shaft assembly, forwardly of the gearcase, such that rotation of the propeller shaft assembly causes rotation of the front and rear propellers, respectively, which thereby propels the marine vessel in the water; and reducing deleterious effects of cavitation on the gearcase by the combination of forming the gearcase with a wide trailing end portion, in particular to maintain pressure alongside the gearcase, and configuring the front and rear propellers so that the front propeller absorbs more torque/thrust load than the rear propeller during said rotation.