WO2007097057A1

WO2007097057A1 - Outboard motor with fuel tank

Info

Publication number: WO2007097057A1
Application number: PCT/JP2006/317690
Authority: WO
Inventors: Daisuke Nakamura; Isao Fujii; Hirotoshi Yamauchi; Ken Wakui
Original assignee: Yamaha Marine Kabushiki Kaisha
Priority date: 2006-02-24
Filing date: 2006-08-31
Publication date: 2007-08-30

Abstract

An outboard motor includes a propulsion unit generating the thrust. An engine powers the propulsion unit. The engine has an engine body. A fuel tank supplies fuel to the engine for combustion. The fuel tank is positioned above the engine body. A first stay extends along a lateral surface of the engine body. The first stay has a first portion and a second portion. The first portion is attached to the lateral surface of the engine body. The second portion supports the fuel tank.

Description

DESCRIPTION OUTBOARD MOTOR WITH FUEL TANK

FIELD OF THE INVENTION

[0001] The present invention generally relates to an outboard motor with a fuel tank, and more particularly relates to an outboard motor having a fuel tank positioned above an engine thereof.

BACKGROUND OF THE INVENTION

[0002] Outboard motors are mounted to an associated watercraft to propel the watercraft forward or backward. Typically, the outboard motors include a drive unit and a mount unit. The mount unit can be fixed to a transom board for mounting the drive unit on the associated watercraft. The drive unit typically includes an engine for powering a propulsion device. The engine includes a crankshaft generally extending vertically as an output shaft of the engine. A driveshaft is coupled with the crankshaft and extends downward from the crankshaft. The crankshaft drives the driveshaft. A propeller shaft is coupled with the driveshaft and can extend generally normal to the driveshaft. Typically, the propeller shaft carries the propulsion device such as, for example, a propeller for generating the thrust. Normally, a casing houses the driveshaft and the propeller shaft. [0003] Some outboard motors have a fuel tank next to the engine. The fuel tank contains fuel to be supplied to the engine for combustion. For example, JP-A-Sho 57- 22997 discloses such an outboard motor. As shown in JP-A-Sho 57-22997, typically, a cowling encloses the engine and the fuel tank for protection.

[0004] The cowling, however, needs to have a fuel inlet port at a portion thereof. Otherwise, the cowling requires a user or operator to remove the cowling whenever the fuel tank is replenished with fuel.

SUMMARY OF THE INVENTION

[0005] A need thus exists for an outboard motor that can protect an engine and a fuel tank without any cowling.

[0006] To address such needs, in accordance with one aspect of the present invention, an outboard motor includes a propulsion unit generating the thrust. An engine powers the propulsion unit. The engine has an engine body. A fuel tank supplies fuel to the engine for combustion. The fuel tank is positioned above the engine body. A first stay extends along a lateral surface of the engine body. The first stay has a first portion and a second portion. The first portion is attached to the lateral surface of the engine body. The second portion supports the fuel tank.

[0007] In accordance with another aspect of the present invention, an outboard motor includes a propulsion unit generating the thrust. An engine powers the propulsion unit. The engine has an engine body. A fuel tank supplies fuel to the engine for combustion. The fuel tank is positioned above the engine body. A stay extends along a lateral surface of the engine body to a lateral surface of the fuel tank. The stay generally has a shape of the inverted letter "L." The stay has a first portion and a second portion. The first portion is attached to the lateral surface of the engine body and extends generally vertically. The second portion extends generally horizontally and is attached to the lateral surface of the fuel tank.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features, aspects and advantages of the present invention are now described with reference to the drawings of a preferred embodiment, which is intended to illustrate and not to limit the present invention. The drawings include seven figures in which:

[0009] FIGURE 1 is a side elevational view (the port side) of an outboard motor configured in accordance with certain features, aspects and advantages of an embodiment of the present invention, an associated watercraft being partially shown; [0010] FIGURE 2 is a side elevational view (the port side) of an upper portion of a drive unit of the outboard motor of FIGURE 1;

[0011] FIGURE 3 is a side elevational view (the starboard side) of an engine and a fuel tank of the outboard motor of FIGURE 1;

[0012] FIGURE 4 is a top plan view of the outboard motor of FIGURE 1; [0013] FIGURE 5 is a rear elevational view of the engine and the fuel tank; [0014] FIGURE 6 is a top plan view of the engine without the fuel tank, the fuel tank and components around the fuel tank and the engine shown in phantom; and [0015] FIGURE 7 is a cross-sectional view of a throttle lever taken along the line 7-7 of FIGURE 2.

DETAILED DESCRIPTION OF THE INVENTION

[0016] With reference to FIGURES 1-7, a structure of an outboard motor 30 which is a preferred embodiment of the present invention will be described below. [0017] With reference to FIGURE 1, the outboard motor 30 in this embodiment has a mount unit 32 and a drive unit 34.

[0018] The mount unit 32 supports the drive unit 34 on a transom board 36 of an associated watercraft 38 and places a marine propulsion device such as, for example, a propeller 40 in a submerged position with the watercraft 38 resting relative to a surface of the body of water. The drive unit 34 can be tilted up (raised) or tilted down (lowered) relative to the watercraft 38.

[0019] As used through this description, the terms "forward" and "front" mean at or to the side where the mount unit 32 is located, unless indicated otherwise or otherwise readily apparent from the context used. Also, the terms "rear," "rearward" and "backward" mean at or to the opposite side of the front side.

[0020] Also, as used in this description, the term "horizontally" means that the subject portions, members or components extend generally parallel to the water surface when the watercraft 38 is substantially stationary with respect to the water surface and when the drive unit 34 is not tilted and is generally placed in the position shown in FIGURE 1. The term

"vertically" means that portions, members or components extend generally normal to those that extend horizontally.

[0021] Additionally, the arrow FWD of FIGURES 1-4 and 6 indicates the forward direction of the associated watercraft 38.

[0022] The mount unit 32 preferably includes a clamping bracket 44, a swivel bracket

46 and tilt pins 47. The clamping bracket 44 is detachably fixed to the transom board 36 by a pair of clamp screw units 48. The swivel bracket 46 is coupled with the clamping bracket

44 by the tilt pins 47 for pivotal movement about axes of the tilt pins 47 extending generally horizontally.

[0023] The swivel bracket 46 carries the drive unit 34 for pivotal movement about an axis of a steering shaft or support tube 49 extending generally vertically. That is, the steering shaft 49 is a top portion of a casing 50 of the drive unit 34 in this embodiment. A driveshaft 52 extends generally vertically through the steering shaft 49. The swivel bracket

46 preferably includes upper and lower bracket body sections 56 through which the steering shaft 49 extends and right and left wing sections 58 extending from the bracket body sections 56. [0024] The casing 50 includes an upper casing 62 and a lower casing 64. The upper casing 62 depends from the steering shaft 49 and extends downward. A top end of the upper casing 62 is preferably coupled with a bottom end of the steering shaft 49. The lower casing 64 depends from the upper casing 62 to further extend downward. A top end of the lower casing 64 is preferably coupled with a bottom end of the upper casing 62. The driveshaft 52 continuously extends vertically and entirely through the upper casing 62 and a bottom end thereof reaches the lower casing 64.

[0025] The lower casing 64 has a power transmission gear unit 66 and a propeller shaft 68. The propeller shaft 68 extends generally horizontally and normal to the driveshaft 52. A front end of the propeller shaft 68 is coupled with the bottom end of the driveshaft 52 through the power transmission gear unit 66. The transmission gear unit 66 is preferably formed with a drive bevel gear positioned at the bottom of the driveshaft 52 and a driven bevel gear positioned at the front end of the propeller shaft 68 and meshing with the drive bevel gear of the driveshaft 52. The propeller 40 is fixed to the propeller shaft 68. [0026] The drive unit 34 preferably includes an internal combustion engine 72. The engine 72 is disposed above the steering shaft 49. That is, a unit housing 74 of a speed reduction unit 76 is fixed to a top end of the steering shaft 49, and the engine 72 is fixed to a top end of the unit housing 74. The speed reduction unit 76 in this embodiment is a planetary gearing mechanism.

[0027] The illustrated engine 72 is an air cooling, single cylinder and four stroke engine. The engine 72 has a crankshaft 77 (FIGURE 4) extending generally vertically. The crankshaft 77 is connected to an input shaft of the speed reduction unit 76, and the input shaft is connected to the driveshaft 52. The rotational speed of the crankshaft is reduced by the speed reduction unit 76. The power of the engine 72 is transmitted to the propeller 40 through the crankshaft 77, the input shaft of the speed reduction unit 76, the power transmission gear unit 66 and the propeller shaft 68. The propeller 40 thus rotates to generate the thrust. The crankshaft 77, the speed reduction unit 76, the power transmission gear unit 66 and the propeller shaft 68 together form a power transmission mechanism 78 of the outboard motor 30.

[0028] The engine 72 has an engine body 80. The engine body 80 includes a cylinder unit 82. A combustion chamber of the cylinder unit 82 is preferably disposed at the rearmost end. An air intake pipe 84 is disposed above the cylinder unit 82 to supply air to the combustion chamber. The air is introduced through an air cleaner 86 positioned at the most-upstream portion of the air intake pipe 84.

[0029] The intake pipe 84 preferably has a carburetor 88 for measuring an amount of the air in accordance with an operation of the engine 72. In order to measure the air amount, the carburetor 88 has a throttle valve 91 (FIGURE 6) which can be operated by a throttle valve control mechanism 90. As is well known, the carburetor 88 also acts as a fuel supply unit. That is, fuel in a fuel tank 94 is also supplied to the combustion chamber through the carburetor 88. More specifically, the carburetor 88 makes air/fuel mixture, and the mixture is delivered to the combustion chamber. An amount of the fuel is also measured in accordance with the air amount. The fuel tank 94 in this embodiment is disposed above the engine body 80.

[0030] The throttle valve 91 is movable between a fully open position and a fully closed position within the carburetor 88. The air can be introduced to the combustion chamber when the throttle valve 91 is placed at any position between the fully open position and the fully closed position, although the air amount changes in response to the opening degree of the throttle valve 91. Meanwhile, the air is blocked from being introduced to the combustion chamber when the throttle valve 91 is placed at the fully closed position. A small passage is preferably provided to deliver nominal air to the combustion chamber for the idling operation of the engine 72.

[0031] As noted above, the fuel is measured in accordance with the air amount. The open position of the throttle valve 91 thus is an allowable position at which the fuel is allowed to flow through a fuel supply conduit. In the illustrated embodiment, the fuel supply conduit is a conduit extending between the fuel tank 94 and the combustion chamber. Also, the closed position of the throttle valve 91 is a non-allowable position at which the fuel is not allowed to flow through the fuel supply conduit. [0032] The air/fuel mixture is burned in the combustion chamber to rotate the crankshaft 77. The burnt charge, i.e., exhaust gases are discharged through an exhaust pipe 96 disposed below the cylinder unit 82. A muffler 98 is preferably coupled with the exhaust , pipe 96 to reduce exhaust noise.

[0033] The throttle valve control mechanism 90 can move a throttle valve of the carburetor 88 between the open position and the closed position. As shown in FIGURES 1, 2, 6 and 7, the throttle valve control mechanism 90 preferably includes a throttle lever 102, a first throttle rod (first link) 104, a second throttle rod (second link) 106, an intermediate lever 108 and an operational member 110. The throttle valve control mechanism 90 in this embodiment is positioned on the left side (port side) surface of the engine body 80 below the fuel tank 94.

[0034] A bracket plate 114 is preferably fixed to the engine body 80 on the left side thereof by bolts 116 to extend generally vertically. The bracket plate 114 in this embodiment is generally positioned below and in front of the fuel tank 94. The bracket plate 114 supports the throttle lever 102 for pivotal movement about a pivot axis 118. One end of the first throttle rod 104 is connected to the throttle lever 102, while the other end of the first throttle rod 104 is connected to the intermediate lever 108. Also, one end of the second throttle rod 106 is connected to the intermediate lever 108, while the other end of the second throttle rod 106 is connected to the operational member 110. The operational member 110 is fixed to a shaft 120 of the throttle valve 91.

[0035] Initially, the throttle lever 102 extends generally vertically upward as shown in FIGURE 1. When the throttle lever 102 is pulled forward as shown in FIGURE 2, through the first throttle rod 104, the intermediate lever 108, the second throttle rod 106 and the operational member 110, the shaft 120 of the throttle valve 91 pivots in a direction in which the throttle valve 91 moves toward the open position. Meanwhile, when the throttle lever 102 is returned to its initial position, the shaft 120 of the throttle valve 91 pivots in a reverse direction in which the throttle valve 91 moves toward the closed position. Such relationships between the movement of the throttle lever 102 and the movement of the throttle valve 91 are natural and reasonable because the forward thrust is generated when the throttle lever 102 is pulled forward.

[0036] Alternatively, a bias spring can normally urge the throttle lever to the initial position. In this alternative, the throttle lever can automatically return to the initial position simply when the operator leaves his or her hand from the throttle lever. [0037] As shown in FIGURES 1, 2 and 7, the bracket plate 114 preferably has a stopper 122 which limits a range of the pivotal movement of the throttle lever 102. That is, when a hooked portion 124 of the throttle lever 102 abuts the stopper 122, the throttle lever 102 is prevented from being further pulled. A support section 128 which is unitarily formed with the intake pipe 84 supports the intermediate lever 108. As best shown in FIGURE 6, the intermediate lever 108 is pivotable about an axis of the support section 128. [0038] In the illustrated embodiment, the throttle lever 102 is generally positioned below and in front of the fuel tank 94 as described above. The operator thus can easily operate the throttle lever 102, for example, with the right hand while sitting in the watercraft 38 and operating a steering handle bar 180 with the left hand. The operator only needs to occasionally take a look at the throttle lever 102. In addition, because the throttle lever 102 is located on the same side as the steering handle bar 180 in this embodiment, the operator can quite naturally operate the throttle lever 102. The operation of the throttle lever 102 is easy and the structure thereof is simple.

[0039] As shown in FIGURE 6, the throttle valve 91 is positioned close to the center line CL in the top plan view, while the throttle lever 102 is located on the left side (port side) of the engine body 80. However, the operational force to the throttle lever 102 can be certainly transmitted to the throttle valve 91 because the intermediate lever 108 is provided between the throttle lever 102 and the throttle valve 91. Because the throttle valve control mechanism 90 is simple, the maintenance service thereof can be easily made. [0040] In addition, the support section 128 of the intermediate lever 108 is unitarily formed with the air intake pipe 84 in this embodiment. The number of parts thus can be decreased so as to make the production costs reduced.

[0041] With reference to FIGURES 1-5, the fuel tank 94 in this embodiment is disposed above the engine body 80, as noted above. Preferably, the fuel tank 94 is made of synthetic resin (plastic) and is formed by blowing using one or more blowing molds. The fuel tank 94 thus is durable against seawater or salty water and can be produced at low costs. More specifically, because being positioned atop the drive unit 34, the fuel tank 94 is hardly submerged in the seawater under a normal running condition. However, such salty water can splash the fuel tank 94. Even though the salty water splashes, the fuel tank 94 made of the resin can sufficiently endure the corrosion by the salty water. [0042] In one variation, the fuel tank 94 can be formed with upper and lower tank members. Both of the tank members can be produced by pressing. The upper and lower tank members can be welded with each other to complete the fuel tank 94. [0043] The fuel tank 94 preferably has side flanges 132 extending outward on both lateral sides of the fuel tank 94. Preferably, the side flanges 132 are disposed at rear end portions on the respective side surfaces of the fuel tank 94. In addition, the illustrated fuel tank 94 has front flanges 134 extending forward from a front end thereof. Preferably, the front flanges 134 are transversely spaced apart from each other, and are symmetrically positioned relative to a center line CL extending fore to aft as shown in FIGURE 4. The flanges 132, 134 can be easily formed as part of mating portions 138 by the blowing molds. [0044] In the illustrated embodiment, the engine 72 has a flywheel magneto. The flywheel magneto preferably extends upward from a top end of the crankshaft 91. A flywheel magneto cover 140 covers the flywheel magneto. The flywheel magneto cover 140 is a portion of the engine body 80 in this embodiment and protrudes upward from a top of the rest of the engine body 80. The fuel tank 94 preferably has a recess 142 at a bottom 143 in a front portion thereof. The recess 142 generally extends from a front end to a center portion of the bottom 143 of the fuel tank 94. The flywheel magneto cover 140 is nested in the recess 142. The fuel tank 94 preferably has an outlet port 144 positioned in the vicinity of the recess 142. More specifically, the outlet port 144 is positioned in the vicinity of the recess 142 and in the rear of the recess 142. Because of this arrangement of the outlet port 144, the fuel in the fuel tank 94 can be entirely consumed with a relatively small pivotal movement of the drive unit 34 in the tilt up direction. The substantial capacity of the fuel tank 94 thus can be increased.

[0045] The engine body 80 preferably supports a rear portion of the fuel tank 94 through a pair of side stays 148, one of which extends along the right side surface of the engine body 80, and the other one of which extends along the left side surface of the engine body 80. Also, the flywheel magneto cover 140 preferably supports a front portion of the fuel tank 94 through a front stay 134 fixed to the flywheel magneto cover 140. A certain space 149 is preferably defined between the bottom 143 of the fuel tank 94 and the top of the engine body 80 including the flywheel magneto cover 140. The illustrated fuel tank 94 does not overhang to the sides of the engine body 80.

[0046] In the illustrated embodiment, a rear half portion of the first throttle rod 104, the intermediate lever 108, the second throttle rod 106 and the operational member 110 of the throttle valve control mechanism 90 are positioned in the space 142 between the fuel tank 94 and the engine body 80 and also between the respective side stays 148. That is, the major part of the throttle valve control mechanism 90 is surrounded by the engine body 80, the fuel tank 94 and the side stays 148 and thus is sufficiently protected by those members 80, 94, 148. [0047] As shown in FIGURES 1, 2, 4 and 6, a starter handle grip 150 for a recoil starter

152 protrudes forward from a front surface of the flywheel magneto cover 140. The operator of the outboard motor 30 can simply pulls the starter handle grip 150 to start the engine operation.

[0048] Each of the side stays 148 is generally shaped as the inversed letter "L" to have a vertical portion 154 and a horizontal portion 156.

[0049] The vertical portion 154 of each side stay 148 preferably extends generally vertically along the lateral side surface of the engine body 80. In the illustrated embodiment, the vertical portion 154 is fixed to a generally center portion of the side surface of the engine body 80 by bolts 158, and extends to a center area of the side surface of the fuel tank 94 positioned generally centrally thereof in the fore to aft direction.

[0050] The horizontal portion 156 of each side stay 148 preferably extends generally horizontally and rearward from a top end of the vertical portion 154. Each horizontal portion 156 preferably has a bracket 160 welded thereto. Each side flange 132 of the fuel tank 94 is fastened to the respective bracket 160 by a bolt 162.

[0051] Preferably, the front stay 134 extends transversely in front of the fuel tank 94 and is welded to a top front portion of the flywheel magneto cover 140. The front flanges

136 of the fuel tank 94 are fastened to the front stay 134 by bolts 164. As shown in

FIGURE 1, the front stay 134 in this embodiment is positioned in front of the center of gravity Gl of the outboard motor 30. Also, as shown in FIGURE 4, the front stay 134 is positioned in front of the crankshaft 77. Because of the arrangement, the front stay 134 can sufficiently support the fuel tank 94 in a stable state.

[0052] The fuel tank 94 has a cap 168 atop thereof. The fuel tank 94 can be filled with fuel by removing the cap 168.

[0053] As shown in FIGURES 3-5, a fuel cock 170 is disposed at a lower portion of the fuel tank 94 on the right side (starboard side) downstream of the outlet port 144 of the fuel tank 94. When the fuel cock 170 is opened, the fuel in the fuel tank 94 is supplied to the carburetor 88 through a fuel delivery pipe 172 connected to the outlet port 144. The fuel delivery pipe 172 is a portion of the fuel supply conduit, which defines the fuel supply passage extending between the fuel tank 94 and the combustion chamber of the engine 72 as discussed above. [0054] In the illustrated embodiment, the center of gravity G2 of the fuel tank 94 is positioned in the rear of the axis of the tilt pin 47 when the fuel tank 94 is filled with a sufficient amount of the fuel. Normally, therefore, the drive unit 34 can extend vertically without any thrust by the propeller 40.

[0055] As shown in FIGURES 1, 2 and 6, a handle bar bracket 176 is preferably positioned at a bottom portion of the engine body 80 on the left side (port side). The handle bar bracket 176 is fastened thereto by bolts 178. A manually operable steering handle bar 180 is attached to the handle bar bracket 176 for pivotal movement about a pivot axis 182. A position of the steering handle bar 180 is adjustable between a fully extended position and a fully retracted position using an arcuately extending slot 184 and a bolt 186 both placed at a base section 188 of the steering handle bar 180.

[0056] For example, the steering handle bar 180 is placed at the fully extended position by fastening the bolt 186 at the position indicated in FIGURES 1 and 2 when the operator steers the outboard motor 30. Meanwhile, the steering handle bar 180 is placed at the fully retracted position by fastening the bolt 186 at the opposite end in the slot 184 when the outboard motor 30 is not operated. When the operator moves the steering handle bar 180 righrward or leftward, the steering shaft 49 pivots to direct the propeller 40 leftward or rightward.

[0057] Alternatively, the steering handle bar 180 can be placed on the right side (starboard side).

[0058] In the illustrated embodiment, a front end 188 of the swivel bracket 46 abuts stoppers 194 fixed to the clamping bracket 44, and the swivel bracket 46 can be tilted up about the axis of the tilt pin 47 from the abutting position. FIGURE 1 shows the outboard motor 30 is in a forward mode. If the operator desires to change the outboard motor 30 to a reverse mode (backward moving mode), the operator rotates the drive unit 34 about the steering axis so as to bring the backside of the drive unit 34 directing forward. Preferably, the drive unit 34 has a hook 196 fixed to the steering shaft 49, while the clamping bracket 44 has a support member 198 fixed thereto. The hook 196 engages with the support member 194 to prevent the drive unit 34 from being raised up by the thrust of the propeller 40.

[0059] The illustrated outboard motor 30 has no cowling that can surround the engine 72 and the fuel tank 94. Thus, seawater or salty water can splash on them. The outboard motor 30, however, can be easily washed by fresh water. In addition, because the space 149 is defined between the top surface of the engine body 80 and the bottom 143 of the fuel tank 94, the engine body 80 and the fuel tank 94 also can be easily washed. More specifically, because of the space 149, the fuel tank 94 and the engine body 80 including the flywheel magneto cover 140 are entirely exposed, the fresh water can go everywhere around the fuel tank 94 and the engine body 80. The seawater thus can be completely washed away. The maintenance service can be easily made, accordingly.

[0060] As discussed above, the illustrated outboard motor 30 has the side stays 148. The operator thus can easily tilt the drive unit 34 about the axis of the tilt pin 47 by pulling the side stays 148 forward. This is quite advantageous because the propeller 40 needs to be almost out of the water body whenever the watercraft 38 moves in shallow water. [0061] In the illustrated embodiment, the axis of the tilt pin 47 is positioned in the rear of the transom board 36 and is placed lower than a top end 202 of the transom board 36. Thus, the distance Ll between the axis of the tilt pin 47 and the center of gravity Glof the outboard motor 30 is shortened. The load of the drive unit 34 under the tilt up condition can be greatly reduced. Therefore, the operator can easily pulls the engine 72 forward by hands to tilt up the drive unit 34.

[0062] Also, as discussed above, the drive unit 34 of the outboard motor 30 in this embodiment has the fuel tank 94 atop thereof. The fuel tank 94 is heavy when filled with a sufficient amount of fuel. Because both of the center of gravity Gl of the outboard motor 30 and the center of the gravity G2 of the fuel tank 94 are positioned in the rear of the axis of the tilt pin 47, the moment that makes the drive unit 34 pivot in its tilt down direction is generated. The drive unit 34 thus is stable under a normal running condition. [0063] The front stay 134 and the right and left side stays 148 in this embodiment can support the fuel tank 94 in preferable balance. Also, the operator can use the side stays 148 as grips when the operator tilts the drive unit 34 up or down. In addition, the side stays 148 can protect the engine body 80 and the engine components around the engine body 80 when the outboard motor 30 is detached from the watercraft 38 and is laid down to the ground, for example.

[0064] Although this invention has been disclosed in the context of a certain preferred embodiment, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiment to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiment may be made and still fall within the scope of the invention. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiment described above, but should be determined only by a fair reading of the claims that follow.

Claims

1. An outboard motor comprising: a propulsion unit generating the thrust; an engine powering the propulsion unit, the engine having an engine body; a fuel tank supplying fuel to the engine for combustion, the fuel tank being positioned above the engine body; and a first stay extending along a lateral surface of the engine body, the first stay having a first portion and a second portion, the first portion being attached to the lateral surface of the engine body, and the second portion supporting the fuel tank.

2. The outboard motor according to Claim 1, wherein the first portion extends generally vertically along the lateral surface of the engine body, and the second portion extends generally horizontally along a lateral surface of the fuel tank.

3. The outboard motor according to Claim 2, wherein the second portion extends rearward from a top end of the first portion.

4. The outboard motor according to Claim 3 further comprising a second stay extending from the engine body to support a front portion of the fuel tank.

5. The outboard motor according to Claim 1 further comprising a second stay extending from the engine body to support the fuel tank together with the first stay.

6. The outboard motor according to Claim 5, wherein the second stay extends transversely in front of the fuel tank.

7. The outboard motor according to Claim 1, wherein the first portion extends generally vertically to a center area of the lateral surface of the fuel tank positioned generally centrally thereof in a fore to aft direction.

8. The outboard motor according to Claim 1 further comprising a pair of the first stays, one of which extends along one lateral surface of the engine body, and the other one of which extends along the other lateral surface of the engine body.

9. The outboard motor according to Claim 1, wherein the engine body includes a protruding portion protruding generally upward from a top surface of the engine, the fuel tank has a recess at a bottom thereof, and the protruding portion of the engine body is nested in the recess.

10. The outboard motor according to Claim 9, wherein an outlet port of the fuel tank is positioned in the vicinity of the recess.

11. The outboard motor according to Claim 10, wherein the recess is formed in a front portion of the fuel tank, and an outlet port of the fuel tank is positioned in the rear of the recess.

12. The outboard motor according to Claim 1, wherein a top surface of the engine body and a bottom surface of the fuel tank are spaced apart from each other.

13. The outboard motor according to Claim 1 further comprising a clamping bracket adapted to be mounted to a watercraft, and a swivel bracket attached to the clamping bracket for pivotal movement about a tilt axis extending generally horizontally, the swivel bracket supporting at least the engine and the fuel tank for pivotal movement about a steering axis extending generally vertically, wherein the center of gravity of the fuel tank is positioned rearward of the tilt axis.

14. The outboard motor according to Claim 1, wherein the fuel tank is formed by blowing.

15. The outboard motor according to Claim 1 further comprising a fuel supply conduit supplying the fuel to the engine from the fuel tank, a fuel supply unit placed between the engine and the fuel tank in the fuel supply conduit, the fuel supply unit having a throttle valve adjusting an amount of the fuel to the engine, and a throttle valve control mechanism controlling the throttle valve, the throttle valve control mechanism including a throttle lever, and the throttle lever being positioned below the fuel tank.

16. The outboard motor according to Claim 15, wherein the throttle lever is generally positioned in front of the fuel tank.

17. The outboard motor according to Claim 15 further comprising a clamping bracket adapted to be mounted to a watercraft, a swivel bracket attached to the clamping bracket for pivotal movement about a tilt axis extending generally horizontally, the swivel bracket supporting at least the engine and the fuel tank for pivotal movement about a steering axis extending generally vertically, and a steering handle pivoting the swivel bracket about the steering axis, wherein the steering handle is positioned on either one of the starboard side and the port side, and the throttle lever is positioned on the same side as the steering handle.

18. The outboard motor according to Claim 15, wherein the throttle valve is movable between an allowable position at which the fuel is allowed to flow through the fuel supply conduit and a non-allowable position at which the fuel is not allowed to flow through the fuel supply conduit, the throttle lever is pivotable about an axis extending transversely, and the throttle valve is placed at the allowable position when the throttle lever is pivoted forward.

19. The outboard motor according to Claim 15, wherein the throttle valve control mechanism comprises an operational member operating the throttle valve, an intermediate lever positioned between the operational member and the throttle lever, a first link connecting the throttle lever to the intermediate lever, and a second link connecting the intermediate lever to the operational member, and a movement of the throttle lever is transmitted to the operational member through the first link, the intermediate lever and the second link.

20. The outboard motor according to Claim 19 further comprising an air intake conduit delivering air to the engine, wherein the air intake conduit supports the intermediate lever for pivotal movement.

21. An outboard motor comprising: a propulsion unit generating the thrust; an engine powering the propulsion unit, the engine having an engine body; a fuel tank supplying fuel to the engine for combustion, the fuel tank being positioned above the engine body; and a stay extending along a lateral surface of the engine body to a lateral surface of the fuel tank, the stay generally having a shape of the inverted letter "L," the stay having a first portion and a second portion, the first portion being attached to the lateral surface of the engine body and extending generally vertically, and the second portion extending generally horizontally and being attached to the lateral surface of the fuel tank.

22. The outboard motor according to Claim 21, wherein the second portion extends rearward from a top end of the first portion.