Lubricant pump seal for outboard motor

A lubricant pump seal for an outboard motor, the outboard motor comprising an internal combustion engine, a water propulsion device, a drive shaft configured to transmit torque from the engine to the water propulsion device, a lubricant pump configured to supply lubricant to the internal combustion engine, the lubricant pump including a pump casing enclosing a pump chamber, the drive shaft extending through the pump casing, a rotor housed in the pump chamber for rotation with the drive shaft, a first sealing body for sealing an upper clearance formed between an upper part of the pump casing and the drive shaft, and second and third sealing bodies for sealing a lower clearance formed between a lower part of the pump casing and the drive shaft, a fourth sealing body is disposed between the second and third sealing bodies in an axial direction of the drive shaft, the fourth sealing body sealing the lower clearance, further comprising a lubricant reservoir and a fluid communication passage between a space in the lower clearance sandwiched between the second and third sealing bodies and the lubricant reservoir.

A lubricant pump seal for an outboard motor, the outboard motor comprising an internal combustion engine, a water propulsion device, a drive shaft configured to transmit torque from the engine to the water propulsion device, a lubricant pump configured to supply lubricant to the internal combustion engine, the lubricant pump including a pump casing enclosing a pump chamber, the drive shaft extending through the pump casing, a rotor housed in the pump chamber for rotation with the drive shaft, a first sealing body for sealing an upper clearance formed between an upper part of the pump casing and the drive shaft, and second and third sealing bodies for sealing a lower clearance formed between a lower part of the pump casing and the drive shaft, a fourth sealing body is disposed between the second and third sealing bodies in an axial direction of the drive shaft, the fourth sealing body sealing the lower clearance, further comprising a cowling enclosing the engine and a fluid communication passage between a space in the lower clearance sandwiched between the second and third sealing bodies and an inside space of the cowling.

An outboard motor comprising an internal combustion engine, a propulsion unit driven by the engine, a housing enclosing the engine and at least a portion of the propulsion unit, a drive shaft extending between the engine and the propulsion unit, a lubricant pump unit configured to deliver lubricant to the engine, the lubricant pump unit including a pump casing and a pump chamber defined within the casing, the drive shaft extending through the lubricant pump unit, a seal disposed between the lubricant pump unit and the drive shaft, and means for using a fluid other than lubricant for relieving a negative pressure generated within the pump casing in the vicinity of the seal but outside of the pump chamber.

An outboard motor comprising an internal combustion engine, a propulsion unit driven by the engine, a housing enclosing the engine and at least a portion of the propulsion unit, a drive shaft extending between the engine and the propulsion unit, a lubricant pump unit comprising a pump chamber and being configured to deliver lubricant to the engine, the drive shaft extending through the lubricant pump unit, a clearance defined between the drive shaft and the lubricant pump unit, at least one seal in contact with the drive shaft and configured to seal the interior of the lubricant pump unit from an exterior of the pump unit, the seal being disposed between a portion of the clearance and the pump chamber, and a passage extending from the portion of the clearance to the exterior of the lubricant pump unit to allow air to bypass all of the seals in contact with the drive shaft and to flow into the portion of the clearance.

An outboard motor comprising an internal combustion engine, a propulsion unit driven by the engine, a housing enclosing the engine and at least a portion of the propulsion unit, a drive shaft extending between the engine and the propulsion unit, a lubricant pump unit configured to deliver lubricant to the engine, the drive shaft extending through the lubricant pump unit, a clearance defined between the drive shaft and the lubricant pump unit, at least one seal in contact with the drive shaft and configured to seal the interior of the lubricant pump unit from an exterior of the pump unit, and a passage extending from the clearance to exterior of the lubricant pump unit, wherein the passage extends to a source of dry air within the housing.

A method of preventing moisture penetration into an interior of a lubricant pump of an outboard motor, the lubricant pump comprising a pump casing and a pump chamber, the method comprising providing a fluid communication passage between the pump chamber and a lubricant reservoir, generating negative pressure within the interior of the pump casing outside of the pump chamber, channeling fluid from a location above the level of liquid lubricant in the lubricant reservoir to the pump casing thereby eliminating the negative pressure.

A method of preventing moisture penetration into an interior of a lubricant pump of an outboard motor, the lubricant pump comprising a pump casing and a pump chamber, the method comprising:

• providing a fluid communication passage between the interior of the lubricant casing at a point outside the pump chamber and a space inside a cowling, generating negative pressure at the point within the pump casing, channeling fluid from the space inside the cowling, but not inside the a lubricant reservoir, to the point within the pump casing, thereby eliminating the negative pressure.