JP2850119B2 - Lubrication system for 4-cycle outboard motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke outboard motor lubrication system.

[0002]

2. Description of the Related Art Conventionally, as a lubricating device for a four-cycle outboard motor, a wet sump type lubricating device described in Japanese Utility Model Laid-Open Publication No. 61-92707 has been proposed. This wet sump type lubricating device has an oil pan (oil reservoir) for storing lubricating oil after lubricating a necessary portion of the engine, which is disposed below the center of the engine body, and a lubrication pump which operates in conjunction with the engine. Is connected to the lower end of the vertical camshaft of the engine, and the lubricating oil in the oil pan is sucked up by this lubrication pump and supplied to the lubrication-required parts of the engine.

[0003]

In the above-mentioned conventional example, the area of a horizontally long oil pan is large, and not only an oil pump connected to a cam shaft is disposed in the oil pan, but also a vertical oil pan. Is inserted through the crankshaft. Both the lubricating oil after lubricating the crank chamber and the lubricating oil after lubricating the camshaft are naturally dropped directly below and returned to the oil pan. However, the exhaust pipe of the internal combustion engine is located immediately below the crankcase, near the drive shaft in front of the outboard motor, and a vertically long oil pan is placed below the rear camshaft, and the oil pan is connected to the oil pan from the exhaust pipe. May prevent heat transfer. The present invention relates to a four-stroke outboard motor,
It is an object of the present invention to smoothly return lubricating oil after lubricating the crank chamber to an oil reservoir when parts necessary for the internal combustion engine are arranged immediately below the crank chamber.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a crank chamber is formed by an inner surface of a half-divided crankcase and a rear surface of a piston of a cylinder block, and a crankshaft is vertically disposed to lubricate an internal combustion engine. In a lubricating device for a four-stroke outboard motor, which lubricates the necessary parts into the oil reservoir and supplies the lubricating oil in the oil reservoir to the lubrication required parts of the internal combustion engine, an intermediate member is provided below the internal combustion engine. An oil return chamber is arranged through the cylinder block, and an oil return path inclined downward from the bottom of the crankcase is formed in the cylinder block. Lubricating oil after lubricating the crank chamber is returned to the oil reservoir through the oil return path. This is referred to as a first configuration. According to the present invention, in the first configuration, an oil receiver is formed in the intermediate member, and a position where the lubricating oil flows into the oil receiver from the oil return path and a position where the lubricating oil flows out from the oil receiver to the oil reservoir. The horizontal separation is a second configuration.

[0005]

1 to 5 show a first related embodiment of the present invention. As shown in FIG. 1, the outboard motor 10 has a clamp bracket 12 attached to a hull 11, a swivel bracket 14 supported on the clamp bracket 12 via a tilt shaft 13 in a tiltable manner, and a swivel bracket 14 The propulsion casing 15 is rotatably supported via a shaft. A four-cycle internal combustion engine 17 is mounted on the upper part of the propulsion casing 15 via a plate-shaped intermediate member 16. 10A is a cowling. The output of the internal combustion engine 17 is transmitted to a propeller shaft 20 via a drive shaft 18 and a forward / reverse switching gear train 19 suspended in the propulsion casing 15 to enable the propeller 21 to rotate forward or backward.

The internal combustion engine 17 is, as shown in FIGS.
This is a four-cycle four-cylinder internal combustion engine with two cylinder blocks.
2. The engine body is formed by the half-divided crankcase 23, cylinder head 24, and head cover 25. Four cylinders are placed horizontally in the cylinder block 22, and a piston 26 is arranged in each cylinder so as to be able to reciprocate in the horizontal direction. The space formed by the cylinder block 22 and the cylinder head 24 on the top surface side of the piston 26 is a combustion chamber 27. A space formed between the inner surface of the crankcase 23 and the back of the piston 26 of the cylinder block 22 is a crank chamber 28. In the crank chamber 28, a crankshaft 29 supported vertically by a bearing formed on a mating surface between the cylinder block 22 and the crankcase 23 is disposed vertically, and an upper end of the drive shaft 18 is provided at a lower end of the crankshaft 29. The parts are connected. Reference numeral 30 denotes a connecting rod that connects the piston 26 and the crankshaft 29.

The space defined by the cylinder head 24 and the head cover 25 is a cam chamber 31. A cam shaft 32 is vertically disposed in the cam chamber 31, and upper and lower ends of the cam shaft 32 are supported by the cylinder head 24. In FIG. 3, 33 is an intake cam, 34 is an exhaust cam, and 35 is a rocker arm. Also,
A belt 38 is wound around a drive wheel 36 provided at an end of the crankshaft 29 projecting from the crank chamber 28 and a driven wheel 37 provided at an end of the camshaft 32 projecting from the cam chamber 31.
The camshaft 32 is rotated once by a half rotation of the crankshaft 29 to open and close an intake valve and an exhaust valve (not shown).

Here, the internal combustion engine 17 constitutes a dry sump type lubricating device. Therefore, as shown in FIGS. 1 to 3, the intermediate member 16 located below the cylinder block 22 has an oil receiving portion.
An oil tank (oil reservoir) 42 is arranged on the side or front of the crankcase 23, and a pump device 43 is arranged on a lower side surface of the cylinder block 22. Thus, the oil tank 42 of this embodiment has a lubricating pump
It is arranged so as to be located below and outside the side region of the lubrication pump 54, that is, in the region above the lubrication pump 54.

At this time, the oil receiver 41 is set in the intermediate member 16 at a position close to the crankshaft 29.
The cylinder block 22 has an oil receiver 41 from the crank chamber 28.
An oil return path 44 extending to the cylinder head 24 is formed.
An oil return path 45 extending from the cam chamber 31 to the oil receiver 41 is formed in the cylinder block 22 and both oil return paths 44,
45 merges at the upper part of the oil receiver 41 and communicates with the oil receiver 41 via a filtration and foam separation screen 46 sandwiched between the cylinder block 22 and the intermediate member 16.
That is, the lubricating oil after lubricating the necessary parts of the engine flows down the oil return paths 44 and 45 by natural fall, and
After passing through 46, it gathers in the oil pan 41.

The oil tank 42 has an oil inflow path 47 and an oil outflow path 48, and has a screen 49 located at an intermediate portion in the tank above the suction port 48A of the oil outflow path 48. The discharge port 47A of the oil inflow path 47 is set so as to protrude above the oil level in the tank, and is separated above the suction port 48A, so that the lubricating oil flowing into the oil tank 42 can be separated into gas and liquid. It is valid. The screen 49 is for filtration and foam separation, and prevents foreign substances and bubbles from flowing into the oil outlet 48 into the suction port side. The oil tank 42 includes an oil inlet cap and an oil level gauge 50. Further, the oil tank 42 is provided with an air bleed pipe 51 for releasing the air in the tank to the upper space of the cam chamber 31 when the oil level in the tank or the tank internal pressure increases, and the air bleed pipe 51 is connected to the oil tank 42. The portion is provided with a check valve 52 to prevent oil leakage when the oil tank 42 falls down due to the tilting of the propulsion casing 15 (see FIG. 2B). The valve opening pressure of the check valve 52 is set by a spring.

The pump device 43 is installed around the lower end of the crankshaft 29, as shown in FIGS. 4 and 5, and includes an oil feed pump 53 and a lubricating pump 54 in a two-stage stacked state in a pump body 43A. Is driven by the torque of the crankshaft 29. That is, a pump shaft drive shaft 56 is coupled to the pump shaft 55, a driven gear 57 is fixed to the pump shaft drive shaft 56, and the driven gear 57 is meshed with a drive gear 58 provided on the crank shaft 29. I have.

As shown in FIG. 4, the oil feed pump 53 has a suction passage 59 provided in the pump body 43A and the cylinder block 22.
Is opened in the oil receiver 41, a discharge path 61A provided in the pump body 43A is connected to a discharge path 61B provided in the cylinder block 22, and the discharge path 61B is connected to the oil inflow path 47 of the oil tank 42. The lubricating oil in the oil receiver 41 is supplied by pressure to the oil tank 42 by the rotation of the rotor 62 fixed to the pump shaft 55. At this time, a check valve 63 is provided in the discharge path 61A in the pump body 43A to prevent the lubricating oil in the oil tank 42 from flowing back to the oil receiver 41 when the outboard motor 10 is placed horizontally. ing. The valve opening pressure of the check valve 63 is set by a spring.

As shown in FIG. 5, the lubricating pump 54 includes a suction passage 64 provided in the pump body 43A and the cylinder block 22.
To the oil outflow passage 48 of the oil tank 42, and the discharge passage 65 provided in the pump body 43A to the oil supply passage 66 provided in the cylinder block 22 and the cylinder head 24,
By the rotation of the rotor 67 fixed to the pump shaft 55, the lubricating oil in the oil tank 42 is pressure-fed to the oil supply path 66 and supplied to the necessary parts of the engine (bearing of the crankshaft 29, bearing of the camshaft 32, etc.). . At this time, a check valve 68 is provided in the discharge passage 65 in the pump body 43A to prevent the lubricating oil fed to the oil feed passage 66 from flowing back to the rotor 67 and set by a spring. When the outboard motor 10 is placed horizontally with the lubrication pump 54 stopped with the engine stopped, the lubrication in the forward direction from the oil tank 42 to the oil supply passage 66 side is performed by the closed valve pressure of the check valve 68. Prevent oil flow.

As shown in FIG. 2, the oil supply passage 66 is connected to a discharge passage 65 of the lubrication pump 54 located below the cylinder block 22 and extends upward from the connection point. And a distribution-side oil supply passage 66B connected to the upper end of the pump-side oil supply passage 66A via an oil filter 69 and extending vertically from the oil filter 69.
There is a branch oil supply passage 66C that branches off from each part of 66B and extends to each lubrication required part of the engine. A transfer oil supply passage 66D is arranged between the bearing at the upper end of the crankshaft and the oil hole 32A of the camshaft 32. The lubricating oil in the uppermost branch oil supply passage 66C lubricates the crankshaft upper bearing, the camshaft upper bearing, the cam surface and the camshaft lower bearing. A relief valve 70 for pressure regulation is provided in the pump-side oil supply passage 66A to the oil filter 69,
The relief valve 70 uses the high pressure of the pump-side oil supply passage 66A as a crank chamber.
Protect the oil filter 69 by escaping to 28.

By reducing the amount of lubricating oil accumulated in the oil receiver 41 and increasing the amount of lubricating oil in the oil tank 42, poor lubrication during restart after tilting up and down is prevented. can do. For this purpose, it is necessary to enhance the pump performance of the oil feed pump that returns the lubricating oil from the oil receiver 41 to the oil tank 42, rather than the pump performance of the lubricating pump that circulates the lubricating oil from the oil tank 42 to the oil receiver 41. In addition, since the lubricating oil on the oil receiver 41 side contains more air than the oil tank 42 side, it is necessary to further improve the pump performance. Therefore, the rotor thickness (capacity) of the oil supply pump 53 is changed to the rotor thickness (capacity) of the lubrication pump 54.
Is larger. The air sent to the oil tank 42 by the oil feed pump 53 increases the tank internal pressure, and the air is discharged to the air bleed pipe 51 described above.

The outboard motor 10 has a drive shaft as shown in FIG.
A water pump 71 driven by 18 is built in the propulsion casing 15 and is driven in conjunction with the internal combustion engine 17.
Thus, external water taken in from the water inlet 72 is supplied to the water jacket 74 of the internal combustion engine 17 through the water supply pipe 73, and the internal combustion engine 17
Is cooled with water.

Next, the operation of the first embodiment will be described. According to the first related embodiment, as described above, the oil tank 42 has a lubricating pump 54
Below and outside the side region, that is, in the region above the lubrication pump 54. Accordingly, there is no suction pipe between the lubrication pump 54 and the oil tank 42 (there is an oil outflow path 48 as a suction path), and the oil level head pressure of the oil tank 42 always acts on the lubrication pump 54. Therefore, outboard motor 10
During the storage of the oil without running out of oil itself,
Lubricating oil can be supplied immediately when the engine is started. In addition,
The oil tank 42 is arranged in the propulsion casing 15 near the tilt axis in the cowling 10A isolated from the exhaust expansion chamber (not shown) formed by the intermediate member 16, so that the oil temperature rise can be suppressed and the tilt up can be achieved. The load can be reduced.

Therefore, according to the first related embodiment, in the four-cycle outboard motor 10, the lubricating oil can be supplied immediately after the start of the engine, and a stable lubricating operation can be always performed.
Further, it is possible to prevent poor lubrication after restarting after tilt up / down. In the above related embodiment, the oil supply system of the oil supply pump 53 always runs out of oil. However, even if the oil feed pump 53 sends air to the oil tank 42, the oil tank 42 performs the gas-liquid separation action as described above, and the lubrication pump 54 can send lubricating oil without air mixing. So no problem. That is, the problem caused by the inflow of air due to oil shortage is the oil supply path from the oil tank 42 to the engine requiring lubrication via the lubrication pump 54. Can be avoided.

FIG. 6 and FIG. 7 show an embodiment of the present invention. As shown in FIG. 6, the outboard motor 110 has a four-cycle internal combustion engine 113 mounted on an upper part of a propulsion casing 111 via an intermediate member 112, as in the case of the outboard motor 10. The internal combustion engine 113 is composed of two cylinders. However, since the basic configuration of each part of the engine is substantially the same as that of the internal combustion engine 17,
The same functional portions as those in 17 are denoted by the same reference numerals, and description thereof is omitted. The point that the internal combustion engine 113 is substantially different from the internal combustion engine 17 is as follows.

That is, since the internal combustion engine 113 constitutes a dry sump type lubricating device, an oil receiver 114 is disposed on an intermediate member 112 located below the cylinder head 24 as shown in FIG. An oil tank 115 (oil reservoir) is arranged at the upper end on the side, and a pump device 116 is arranged at the lower end of the cam shaft 32. At this time, the oil receiver 114 is connected to the cam shaft 32 of the intermediate member 112.
It is installed at a position close to. Cylinder block 22
The oil tank 115
And extends in the front-rear direction of the outboard motor toward the oil receiver 114,
A downwardly inclined oil return path 44A is formed, and the upper end of the oil return path 44A is formed with a lubricating oil drop hole 23A.
Is opened at the bottom of the crank chamber 28 through the oil return path.
The lower end of 44A is open at the upper part of oil receiver 114. An oil return path 45 extending from the cam chamber 31 to the upper part of the oil receiver 114 is formed in the cylinder head 24, and both oil return paths 4
4 and 45 meet at the upper part of the oil receiver 114. It communicates with an oil receiver 114 via a screen 46 for filtering and separating bubbles which is held between the cylinder block 22 / cylinder head 24 and the intermediate member 112. That is, the lubricating oil after lubricating the necessary parts of the engine flows down the oil return paths 44A and 45 by natural fall, and passes through the screen 46 to receive the oil.
Gather at 114. The position where the lubricating oil flows into the oil receiver 114 from the oil return path 44A and the position where the lubricating oil flows out from the oil receiver 114 to the oil tank 115 are separated horizontally.

The oil tank 115 has a propulsion casing.
A check valve 117 disposed at a position close to the camshaft 32 at the rear upper end of the
A, an oil inflow pipe 117 and an oil outflow pipe 118, and a screen 119 located at an intermediate portion in the tank, which is higher than the valved suction port 118A of the oil outflow pipe 118. The oil tank 115 has an oil inlet cap and an oil level gauge 120. Further, the oil tank 115 is provided with an air bleed pipe 121 for allowing the air in the tank to escape to the upper space of the cam chamber 31 when the oil level rises. Oil tank due to tilting of casing 111
A check valve 122 is provided in order to prevent oil leakage at the time of falling of the engine 115 and the like. The valve opening pressure of the check valve 122 is set by a spring. The valve of the suction port 118A with a valve has the same function as the check valve 68 of the first related embodiment, and when the outboard motor 110 is placed horizontally with the lubrication pump 124 stopped with the engine stopped, etc. To prevent the flow of the lubricating oil in the forward direction from the oil supply passage 132 to the oil supply passage 132 side. The check valve 117A is of the first related form 63
It has the same function as (check valve).

The pump device 116 is disposed around the lower end of the camshaft 32 as shown in FIGS.
3 and a lubrication pump 124 are provided in a two-tiered state in the pump body 116A, and a pump shaft 125 common to both is directly connected to the lower end of the cam shaft 32. Oil pump 123 is a pump
A suction port 127 of a suction passage 126 provided in 116A is opened to an oil receiver 114, and a discharge passage 128 provided in a pump body 116A, a cover 116B, and an elastic seal member 134 is connected to an oil inflow pipe 117 of an oil tank 115. The lubricating oil in the oil receiver 114 is fed by the rotation of the rotor 129 fixed to the pump shaft 125 and supplied to the oil tank 115.

At this time, the discharge passage 128 in the pump body 116A is
Is provided with a check valve (not shown) to prevent the lubricating oil in the oil tank 115 from flowing back to the oil receiver 114 when the outboard motor 110 is placed horizontally. The lubrication pump 124 has a suction passage 130 provided in the pump body 116 A, the cover 116 B, and the elastic seal member 134, and is connected to the oil outflow pipe 11
8, a discharge passage 131 provided in the pump body 116A is connected to an oil feed passage 132 provided in the cylinder block 22 and the cylinder head 24, and the rotation of a rotor 133 fixed to a pump shaft 125 causes the oil tank to rotate. The lubricating oil 115 is pressure-fed from the oil supply path 132 and supplied to the lubrication-required parts of the engine (bearing of the crankshaft 29, bearing of the camshaft 32, etc.). Below the oil tank 115, a drain plug 115A is provided.

At this time, the discharge passage 131 in the pump body 116A
Is provided with a valve (not shown) that opens when pressure is applied, prevents the lubricating oil fed to the oil feed passage 132 from flowing back to the rotor 133, and sets the valve by a spring. The valve closing pressure prevents the flow of the lubricating oil in the forward direction from the oil tank 115 to the oil feed passage 132 when the outboard motor 110 is placed sideways with the lubrication pump 124 stopped with the engine stopped. In FIG. 6, an intermediate portion of the cooling water supply pipe 73 is an adhesive 13 containing a metal such as aluminum which is a good heat conductor.
4 is attached to the side wall of the oil tank 115 so that the lubricating oil in the oil tank 115 can be water-cooled. In FIG. 6, reference numeral 135 denotes an exhaust pipe.

Next, the operation of the above embodiment will be described. According to the above-described embodiment, the oil tank 115 is provided at a lower position near the camshaft 32, and the lubrication pump 124 is installed at the lower end of the camshaft 32. This allows the oil tank
The lug 115 is arranged so that the oil level of the oil tank 115 is located below the lubricating pump 124 and outside the side region, that is, substantially immediately below the lubricating pump 124. Therefore, lubrication pump 124
An oil outflow pipe 118 as a suction pipe extending from the oil tank 115 to the oil tank 115 is substantially straight and short. Accordingly, the length of oil cut-off generated in the oil outflow pipe 118 during storage of the outboard motor 110 is reduced, and lubricating oil can be supplied immediately when the engine is started. Therefore, according to the above-described embodiment, in the four-cycle outboard motor 110, the lubricating oil can be supplied immediately after the start of the engine, and a stable lubricating operation can always be performed.

An exhaust pipe 135 is disposed immediately below the crank chamber 28 in front of the outboard motor 110, and an oil tank 115 is disposed behind the outboard motor. Since the oil return path 44A inclined downward to the receiver 114 is formed, the lubricating oil after lubricating the crank chamber 28 can return to the oil tank 115 and the oil receiver 114 by natural fall, and the crank chamber 28 The members necessary for the internal combustion engine 113 can be arranged below the lower part. Then, the oil is received from the oil return path 44A.
Since the position where lubricating oil flows into 114 and the position where lubricating oil flows out from oil receiver 114 to oil tank 115 are horizontally separated, oil tank 115 is separated from crank chamber 28 by an arbitrary distance in plan view. When the oil tank 115 and the crank chamber 28 are separated in the front-back direction, the distance can be increased. When trimming the boat, the lower end of the outboard motor is moved rearward and the upper end of the longitudinal axis of the outboard motor is tilted forward by the trim angle, but the tilt angle of the lower surface of the oil return path 44A is trimmed. Since the angle is larger than the angle, the lubricating oil after lubricating the crank chamber 28 can return to the oil tank 115 and the oil receiver 114 by natural fall even during trim running.

FIG. 8 shows a second related form of the present invention. As shown in FIG. 8, the outboard motor 140 is substantially the same as the outboard motor 110, and the same functional portions as those in the outboard motor 110 are denoted by the same reference numerals and description thereof will be omitted. This outboard motor 140 is
The difference from 110 is that an oil receiver 114A is provided at a position between the crankshaft 29 and the camshaft 32 in the intermediate member 112, and an oil feed pump 123 is provided on the pump body 116A, the cylinder head 24, and the intermediate member 112. That is, the suction pipe 127A connected to the suction passage 126A is opened to the oil receiver 114A.

At this time, in the second embodiment, the oil tank 115 is provided at a lower position close to the camshaft 32 and the lubrication pump 124 is provided at the lower end of the camshaft 32, as in the previous embodiment. It was installed in. Therefore, the oil tank 11
5 is positioned so as to be located substantially immediately below the lubrication pump 124. As a result, the lubrication pump 124
The oil outflow pipe 118 as a suction pipe extending to 5 becomes a straight pipe and becomes short. Accordingly, the length of oil cut-off generated in the oil outflow pipe 118 during storage of the outboard motor 140 is reduced, and lubricating oil can be supplied immediately when the engine is started. As a result, in the four-cycle outboard motor 140, the lubricating oil can be supplied immediately after the start of the engine, and a stable lubricating operation can always be performed.

In FIG. 8, the middle portion of the water supply pipe 73 is also attached to the bottom wall of the oil receiver 114A by the above-mentioned adhesive 134, so that the lubricating oil in the oil receiver 11A can be water-cooled.
Further, the present invention is not limited to the dry sump type lubricating device including the oil receiver and the oil tank as in the above-described related embodiments and embodiments, but also applies the return lubricating oil of the engine to an oil pan (oil reservoir) below the engine. The present invention can also be applied to a wet sump type lubricating device which supplies the lubricating oil to a required portion of the engine by a pump. That is, in the case of the wet sump type, the oil sump is arranged so as to be located substantially immediately below the lubrication pump, and the oil level of the oil sump is positioned below the lubrication pump and outside the side area. Is set.

[0030]

According to the first aspect of the present invention, an oil return path inclined downward from the bottom of the crankcase is formed in the cylinder block, and parts necessary for the internal combustion engine are arranged immediately below the crankcase. Thus, the lubricating oil after lubricating the crank chamber can be smoothly returned to the oil reservoir.
Then, necessary members can be arranged directly below the crank chamber. According to the second aspect, an oil receiver is formed in the intermediate member, and a position where the lubricating oil flows into the oil receiver from the oil return path and a position where the lubricating oil flows out from the oil receiver to the oil reservoir are horizontally separated. Therefore, the range of selection of the position where the oil reservoir is arranged is further expanded.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a four-cycle outboard motor to which a first related embodiment of the present invention is applied.

2 (A) is a partially broken side view showing the four-stroke internal combustion engine of FIG. 1, and FIG. 2 (B) is an enlarged sectional view of a main part of FIG. 2 (A).

FIG. 3 is a sectional view showing the four-stroke internal combustion engine of FIG. 1;

FIG. 4 is a sectional view showing an oil feed pump system in the pump device of FIG. 1;

FIG. 5 is a sectional view showing a lubrication pump system in the pump device of FIG.

FIG. 6 is a side sectional view schematically showing a lubrication device for a four-cycle outboard motor to which an embodiment of the present invention is applied.

FIG. 7 is a sectional view showing the pump device of FIG. 6;

FIG. 8 is a side sectional view schematically showing a lubricating device for a four-cycle outboard motor to which a second related embodiment of the present invention is applied.

[Explanation of symbols]

 22 Cylinder block 23 Crankcase 26 Piston 28 Crankcase 29 Crankshaft 44A Oil return path 112 Intermediate member 113 Internal combustion engine 114 Oil receiver

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01M 11/00 F01M 1/06

Claims (2)

(57) [Claims] 1. A lubrication system comprising: a crank chamber formed by an inner surface of a half-divided crankcase and a rear surface of a piston of a cylinder block; a crankshaft arranged vertically; In a lubrication system for a four-cycle outboard motor, which allows oil to flow into an oil reservoir and supplies lubricating oil in the oil reservoir to a portion requiring lubrication of the internal combustion engine, the oil reservoir is disposed below the internal combustion engine via an intermediate member. A four-stroke cycle wherein an oil return path inclined downward from the bottom of the crankcase is formed in the cylinder block, and lubricating oil after lubricating the crank chamber is returned to the oil reservoir through the oil return path. Outboard motor lubrication system. 2. An oil receiver is formed in the intermediate member, and a position at which lubricating oil flows into the oil receiver from the oil return path;
The lubricating device for a four-stroke outboard motor according to claim 1, wherein a position where the lubricating oil flows out from the oil receiver to the oil reservoir is horizontally separated.