Abstract: An outboard motor includes an improved engine layout to provide a compact power head while simplifying the arrangement of components on the engine. In one mode, an induction system of the engine includes a carburetor that is arranged over a cylinder head. An intake pipe connects the carburetor to an intake port of the cylinder head. The pipe has generally a U-shape and loops around the upper side edge of the cylinder head. An air intake device is arranged upstream of the carburetor to supply air thereto. The air intake device includes a downward facing air intake opening that is located along a side of the engine below the upper end. This arrangement of the induction system that extends over the upper side of the engine produces a compact assembly without overly complicating the arrangement of other components on the engine, such as, for example, a manual starter device.

Abstract: An outboard motor throttle and transmission control that employs a bowden wire mechanism for transmitting control signals from the tiller handle to the engine throttle and transmission control. The control handle is pivotally mounted on the front end of a tiller arm and the wire actuators exit the control handle and enter the protective cowling on opposite sides of a longitudinal center plane or on opposite sides of the protective cowling so as to increase the length of the wire actuators in this area so as to facilitate their bending without kinking.

Abstract: One embodiment of an engine has an electrical system generally comprising a charge circuit and an ignition circuit. A primary power supply circuit connects the charge circuit and the ignition circuit through a non-contact switch circuit. The non-contact switch is adapted to connect the primary power supply circuit to the ignition circuit when the engine is started. A secondary power supply circuit is coupled to at least one electrical component and to the ignition circuit. The secondary power supply circuit has a main switch and a fuse arranged upstream of the main switch. Upon closing the main switch, the engine is started and the primary power supply circuit and the associated non-contact switch are closed. Another embodiment of the engine has an electrical system which adds control of a fuel injector circuit. The fuel injector circuit is in electrical communication with the ignition circuit and a switching circuit which controls the ignition circuit and the fuel injector circuit.

Abstract: A crankcase ventilation system is provided for an outboard motor having a cowling and a water propulsion device, an internal combustion engine positioned in the cowling and arranged to propel the water propulsion device. The engine having at least one combustion chamber, a crankcase chamber into which blow-by air and fuel from the combustion chamber passes, a lubricating system including an oil filter and an ignition system including an ignition element for initiating combustion in said combustion chamber. The crankcase ventilation system includes an air intake member defining an intake chamber, at least one air intake port providing a source of air for the engine communicating with the intake chamber and an output port in fluid communication with the intake chamber for delivery of the air to the engine from the intake chamber. At least one blow-by port directs blow-by mixture from the crankcase chamber into the intake chamber at a point on the air intake member between the intake port and the output port.

Abstract: An outboard motor cooling system wherein the coolant is circulated through the various cooling jackets so that it first flows into proximity with at least a portion of the exhaust system cooling jacket and then into the cooling jackets of the main engine body that cool the cylinder bore and combustion chamber. Sacrificial anodes are positioned both in the main engine body cooling jacket and in the exhaust system cooling jacket. In addition, a temperature sensor is positioned in a low portion of the cooling jacket and where the water has passed through the exhaust cooling jacket and before it enters the main engine body cooling jacket so as to provide accurate temperature indication while protecting the temperature sensor from excess temperature conditions particularly after engine shut off.

Abstract: Several embodiments of outboard motors having four cycle internal combustion engines wherein one or more fuel pumps are directly driven by the lobes of the camshafts that operate the valves of the engine. This provides a very compact assembly, permits latitude in the location of the fuel pump or pumps and also minimizes the number of driving connections that are required.

Abstract: A cowling latch for an outboard motor having an upper cowling having a lower surface and a lower cowling having an upper surface is disclosed. The cowling latch comprises a first latching member connected to the upper cowling and a second latching member connected to the lower cowling. The second latching member is moveable between a first position in which it engages the first latching member for connecting the upper and lower cowlings and a second position in which it does not engage the first latching member. The second latching member comprises a first latching member engaging part movably mounted with respect to a support, the support positioned below the upper surface of the lower cowling.

Abstract: Several embodiments of improved security systems for marine propulsion systems that do not have a continuously available source of electrical energy. These systems include an electric key reader that is powered by a manually operated electrical power supply during starting so as to ensure against theft. In one embodiment, if there is a failure in the electrical power supply for the security system, the speed of the propulsion system is limited so that a rightful owner can reach an area where service can be obtained.

Abstract: A crankshaft bearing support arrangement is disclosed for an engine arranged such that the crankshaft is vertically oriented. The crankshaft rotates within a crankcase chamber defined by the cylinder block and a crankcase cover connected thereto. First web members which support half-bearings extend from the cylinder block. Mating half-bearings are supported by second web members position opposite the first web members. An oil flow passage is defined through the crankcase chamber generally opposite the cylinder block from a top end to a bottom end of the chamber. In one arrangement, the oil flow passage comprises individual passages through the second web members. In another arrangement, the oil flow passage comprises a space between an end of the second web members opposite the cylinder block and the crankcase cover.

Abstract: A shift and throttle control mechanism allows for control of the shift and throttle features of an outboard motor through two separate operators. For instance, one operator can be remotely positioned in the hull of an associated watercraft, while the other operator can be formed on a steering handle of the outboard motor. The shift and throttle control mechanism is also configured to fit within a cowling of the outboard motor, together with a four-cycle engine, without significantly increasing the size of the cowling. In one mode, the shift and throttle control mechanism includes a shift shaft arranged toward the front side of the engine. One of the operators is directly connected to shift shaft by a linkage rod. The other operator is connected by a shift control cable to a shift lever that is located on the side of the engine. This location of the shift lever allows the end of the shift control cable to be fixed within the cowling without increasing the cowling's size.

Abstract: An outboard motor embodying a four-cycle internal combustion engine having a decompression device for automatically reducing the compression ratio to assist in pull starting. The decompression device is mounted and operated through one end of the cam shaft and thus facilitates modification of engines so as to incorporate this feature or not incorporate the feature. The construction also facilitates lubrication of a centrifugal mechanism that actuates the decompression device.

Abstract: An outboard motor outer cover arrangement The outboard motor is comprised primarily of a powerhead and a drive shaft housing and lower unit which depends from the powerhead. The powerhead is comprised of an internal combustion engine and a surrounding protective cowling. The protective cowling comprises a lower tray portion and a detachable main cowling portion that is detachably connected to the tray portion. An exhaust guide is provided at the upper end of the drive shaft housing and lower unit and the engine is supported on this guide plate as is the tray. A cover is detachably connected to the underside of the exhaust guide and is positioned in partially surrounding relationship to the upper portion of the drive shaft housing and lower unit so as to provide a neat appearance.

Abstract: An exhaust manifold for an outboard motor that has a vertically extending crankshaft and which exhaust manifold is formed in the cylinder head and cylinder block. The cylinder block forms the exhaust manifold by runner sections that are configured in such a way so as to facilitate the casting process by which they are formed and which provide an effective smooth flow path without requiring complex cores or patterns.

Abstract: An outboard motor having a direct cylinder fuel injection system with a high-pressure pump that is driven directly from the engine crankshaft. This drive is positioned on the crankshaft above the flywheel at the upper portion of the engine, with other accessories being driven from the crankshaft below the flywheel, while still at the top of the engine. This facilitates servicing of the components and places them all in easily accessed locations.

Abstract: An improved thrust taking arrangement for an outboard drive includes an anti-friction member that transfers the thrust between the trim adjusting thrust member and the outboard drive. The anti-friction member is attached on the thrust taking member and is made of a material having a smaller coefficient of friction than both of the thrust member and the thrust taking member for reducing friction upon reciprocation of the thrust member.

Abstract: A feed back control system and method for direct injected engines, particularly useful in marine applications to avoid knocking. Different types of injection control are applied to achieve this depending on the engine running condition when knocking occurs. Both injection initiation and duration are controlled. Injection timing is employed primarily to control knocking under steady state running. Both injection initiation and duration are controlled to avoid knocking under acceleration.

Abstract: A fuel supply system for providing fuel from a fuel source to a combustion chamber of an engine is disclosed. The fuel supply system includes a vapor separator in which vapor is separated from fuel supplied from the fuel source. A pre-pressurizing pump pressurizes fuel from the vapor separator to a first pressure and delivers it to a high pressure pump. The high pressure pump pressurizes the fuel to a pressure above the first pressure and delivers it to a fuel rail to which is connected a fuel injector for delivering fuel into the combustion chamber. A fuel return line extends from the fuel rail for returning undelivered fuel back to the fuel system. A valve controls the flow of fuel through the return line and maintains the fuel at high pressure in the fuel rail. A fuel cooler is provided along the return fuel line.

Abstract: A feed back control system and method for direct injected engines, particularly useful in marine applications to improve transitional operation. This is done by effecting a change in engine speed by effecting a change in fuel injection to a cylinder subsequent to the cylinder being supplied with fuel at the time the change in speed is called for.

Abstract: An improved and simplified outboard motor construction wherein the cooling and exhaust systems for the engine are formed with a minimum number of components and sealing joints. The exhaust system includes an elongated expansion chamber formed in the drive shaft housing. In addition, the drive shaft housing has a cylindrical section that is journaled within a swivel bracket for its steering movement. The volume between the external portion of the drive shaft housing and the internal portion of the swivel bracket forms a second expansion chamber that is employed for the low speed above the water exhaust gas discharge. The flow of cooling the water to and from the engine is controlled so that the exhaust gas interchange area between the power head and the drive shaft housing will be well cooled, as will the oil reservoir for the engine and the oil returned to it.