Abstract: A lubricating system 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 crankshaft support members which support half-bearings extend from the cylinder block. Mating half-bearings are supported by second crankshaft support members positioned opposite the first crankshaft support members. A baffle plate is positioned in the crankcase chamber between the crankcase cover and the crankshaft. At least one oil flow passage is defined through the crankcase chamber from a top end to a bottom end of the chamber. In one embodiment, oil is supplied through a main passage in the crankcase cover and a branch passage through each second crankshaft support members for lubricating the bearings.

Abstract: A tilt and trim arrangement for marine propulsion includes an improved construction. A swivel bracket, which carries a drive unit for pivotal movement about a steering axis includes a pair of ribs spaced apart transversely from each other. A clamping bracket is affixed to an associated watercraft and supports the swivel bracket for pivotal movement about a tilt axis. A hydraulic tilt device is provided for tilting the swivel bracket. The tilt device includes a cylinder housing, a piston slidably supported within the housing and a piston rod affixed to the piston. The cylinder housing has an upper section with a diameter that is smaller than a lower section, and the piston rod extends outwardly from the upper section. The piston rod is pivotally affixed to the ribs. The upper section of the cylinder housing is generally positioned between the ribs at least when the piston rod is fully retracted within the cylinder housing.

Abstract: An engine includes an electronic controller which samples the pressure in the induction system once per rotation of the crankshaft. The controller is configured to determine the minimum voltage signal output by the pressure sensor. The controller then uses the minimum pressure sensed by the pressure sensor to control the fuel injection of the engine. The controller may include two and/or three dimensional maps for predicting the appropriate timing for sampling the pressure sensor. Optionally, the controller may include a bottom hold device for holding a minimum value of the signal output from the pressure sensor, thus corresponding to the minimum pressure sensed by the pressure sensor.

Abstract: A four stroke engine having at least two cylinders spaced vertically relative to each other. Each cylinder includes a cylinder body having a cylinder bore extending generally horizontally. Plurality of air intake ducts are provided for connecting a common plenum chamber and respective air intake passages which extends to respective combustion chambers. Each of the air intake ducts has a generally straight section extending generally horizontally and parallel to each other. The distance between the straight sections is less than the distance between the axes of the cylinder bores. Also, in another feature, throttle body means are interposed between duct members, which are upstream components of the air intake ducts, and the intake passages for controlling the flow of air to the combustion chambers.

Abstract: A protective cowling arrangement for the power head of an outboard motor and an air inlet arrangement therefor. The cowling arrangement is comprised of a cowling portion that defines an internal area in which the engine of the outboard motor is contained and a pair of expansion chambers formed on opposite sides of the cowling assembly and each of which is provided with a respective air delivery port at a forward end thereof for increasing the air flow area available to the interior of the cowling assembly and for placing the point of air admission away from components of the associated engine that should be protected. An improved water gutter and drain arrangement is also employed to prevent water from entering into the engine area.

Abstract: An exhaust system for an outboard motor includes an improved construction that can reduce cost for providing an expansion chamber of an idle exhaust discharge. The outboard motor includes an engine and a protective cowling that surrounds the engine. The protective cowling includes a top and bottom cowling members. The expansion chamber of the idle exhaust route is defined by at least a bottom surface of the bottom cowling member and a separable member.

Abstract: A marine outboard drive, such as an outboard motor, includes both a splash plate and an anti-splash device. The anti-splash device includes a second splash plate that is provided on a lower mount, which couples together a swivel bracket and a drive housing. The second splash plate extends generally forwardly of the swivel bracket just under a lower portion of a clamp bracket that supports the swivel bracket. The anti-splash device preferably also includes a guide that is provided above the conventional splash plate for directing splashed water rearwardly so that the water is guided away from a mount cover that covers the lower mount. These features of the anti-splash device are particularly useful when the outboard drive is used with a pontoon boat.

Abstract: An outboard motor engine includes a plurality of cylinders. A fuel injector is disposed to inject a charge of fuel into an intake system. The fuel injector can form a portion of a direct injection system or a manifold injection system. The engine includes a processor that cycles each of the fuel injectors prior to energizing a fuel pump, a starter motor, or another electrical component of the outboard motor. By energizing the fuel injectors in sequence, a higher level of voltage can be applied to each fuel injector. In addition, by energizing the fuel injectors prior to energizing other electrical components, a higher level of voltage can be applied to each fuel injector.

Abstract: A direct fuel injected engine includes an improved construction for preventing a fuel injector from holding considerable heat therein. A cylinder head of the engine has a cavity opened to a combustion chamber. A fuel injector is placed within the cavity and is arranged to directly spray fuel into the combustion chamber. At least one heat insulator is disposed between the cylinder head and the fuel injector to insulate the fuel injector, at least in part, generally from the cylinder head.

Abstract: An improved arrangement of an outboard motor reduces the size of the outboard motor and improves a lubrication system of the outboard motor. Intake and exhaust passages are located along a side of a cylinder body. A crank case lubricant return passage is located on the same side of the cylinder body as the intake and exhaust passages. The return passages have openings located on an inner surface of the crank case. A breather passage connecting a cam chamber and an lubricant reservoir are located on a side of the cylinder body opposite the intake and exhaust passage. The lubricant reservoir including a drain and an insertion port. The insertion port being pointed towards the drain.

Abstract: A fuel supply system for use with an engine having four vertically-arranged cylinders and multiple charge formers prevents air or vapor pockets from accumulating within the fuel pump or fuel lines. A pair of fuel pumps are mounted vertically one above the other. A fuel inlet port of each pump is formed at the lower-most portion of the pump. A fuel discharge port is formed at the upper-most portion of each port. A conduit attached to the top fuel pump's discharge port supplies fuel to an uppermost and lowermost carburetor. A conduit from the lowermost fuel pump supplies fuel to the middle two carburetors. The uppermost carburetor's fuel inlet port is positioned vertically higher than the top fuel pump's discharge port. The second carburetor's fuel inlet port is positioned vertically higher than the second fuel pump's discharge port.

Abstract: An improved overheat detection system for an engine having at least one coolant jacket which is drained of coolant when the engine is not running. The coolant jacket has an inlet portion into which the coolant is supplied and an outlet portion from which the coolant is discharged during the engine is running. In one feature of this invention, the overheat detection system has a sensor for sensing a temperature associated with the coolant jacket at an aft part of the coolant jacket including the outlet portion. In another feature of this invention, the overheat detection system has at least two sensors, one is positioned at a fore part of the coolant jacket including the inlet portion and another is positioned downstream of the former sensor, and both sensors for sensing each temperature associated with the coolant jacket. The overheat detection system is arranged to output an overheat signal in the event the temperature sensed by the sensor or at least one of the sensors is above a predetermined temperature.

Abstract: An exhaust system for an outboard motor wherein the exhaust pipe which depends into the expansion chamber formed in the drive shaft housing is provided with a separate cooling jacket. Water from this separate cooling jacket is discharged into the expansion chamber at a point well below the discharge end of the exhaust pipe in a direction away from the exhaust pipe so as to avoid water ingestion into the engine through the exhaust system. A second expansion chamber communicates with an above the water exhaust gas discharge. This second expansion chamber communicates with the first expansion chamber through a restricted path formed in part by a flange of the exhaust pipe.

Abstract: An outboard motor has a fuel injected internal combustion engine operating on either a two-cycle or four-cycle principle. In some embodiments, the engine is directly injected while in others it is indirectly injected. The engine features one of a number of methods for reducing the temperature of injector drivers. The methods include sensing the temperature of the injector drivers and decreasing the engine speed if the temperature exceeds a predetermined temperature. Another method involves sensing the duration of a high-speed, high-load operating condition and slowing the engine speed if the duration exceeds a predetermined time period. Yet another method involves activating a cooling fan if the temperature of the injector drivers exceeds a predetermined temperature and activating a warning device if the temperature does not decrease with the fan operating.

Abstract: An improved shift mechanism for a marine propulsion transmission is provided. The shift mechanism includes a guide that defines a slot that receives a member of a linkage that connects an operator unit with a shift rod. Movement of the shift mechanism is converted into substantially linear motion and a shift position sensor is located at a substantially right angle to that movement. Information from the sensor is transmitted to a control unit and is employed to prevent abrupt starts. The shift position sensor is located on the side of an engine for ease of assembly and maintenance. Movement of the shift mechanism may also cause pivotal movement of the guide and this pivotal movement may be employed to reduce the engine speed and assist shifting.

Abstract: A driveshaft housing for an outboard motor includes an improved construction. The outboard motor comprises a power head containing an engine, the driveshaft housing depending from the power head and containing a driveshaft, and a lower unit depending from the driveshaft housing and supporting a propulsion device. The engine includes an exhaust system having an exhaust conduit at least in part extending through the driveshaft housing. The driveshaft housing has a rib extending from one lateral side wall portion to another lateral wall portion between the driveshaft and the exhaust conduit. The stiffening rib strengthen the rigidity of the lateral side walls of the driveshaft housing, and thereby inhibits inward and outward movement of the lateral side walls, particularly in a region where the walls define a portion of an expansion chamber of the exhaust system within the driveshaft housing.

Abstract: A blow-by gas ventilation system for a crankcase of an engine includes an improved construction for distributing blow-by gases more evenly between multiple cylinders. The engine has an air intake device that includes a plurality of air delivery conduits for the cylinders and a plenum chamber housing disposed upstream of the air delivery conduits. The ventilation system comprises a blow-by gas conduit that couples the crankcase with the plenum chamber housing. The plenum chamber housing includes an opening to which the blow-by gas conduit is connected. A baffle is disposed in front of the opening within the plenum chamber housing so as to divide the blow-by gases equally for the respective cylinders.

Abstract: A direct injection system and control methodology for two-cycle crankcase compression engines wherein the injection timing is advanced from those normally utilized to avoid the incomplete combustion that results from the prior art method. The injection timing is advanced so that it occurs while the exhaust port is still open but it is timed in such a way that the injected fuel will not be swept out of the exhaust port before the exhaust port closes and so that the fuel will vaporize adequately to be completely burned. The initiation of injection timing is adjusted in response to in combustion chamber air velocity determined by certain parameters such as engine speed and intake air flow.

Abstract: An outboard motor has an induction system and a fuel supply system. The two systems are linked together to improve responsiveness of the fuel supply system based upon fluctuations in pressure within the induction system. The motor includes an induction air pressure detection system. The detection system comprises a pressure sensor and a connection to at least two different air intake pipes of the induction system. The connection between the sensor and the two pipes is configured such that the distance between the sensor and each of the pipes is the same. The detection system is configured to sample the pressure in multiple intake pipes associated with multiple cylinders using connecting conduits that have the same length from each intake pipe to the pressure sensor.

Abstract: A fuel filter for an internal combustion engine suitable for detecting water accumulated therein. The fuel filter has a holder that is mounted on the engine and holds a filter body. A vessel is detachably affixed to the holder. There is a space between the end of the filter body and the bottom of the vessel. An inlet and outlet are provided for inducing fuel into and discharging it from the vessel. The inlet and outlet are connected relative to each other through the filter body for admitting flow of the fuel. In one feature of this invention, a water detection mechanism is placed under the filter body in the vessel. In another feature of this invention, the vessel is made of a transparent material. In a further feature, the holder is mounted on the engine via a damping member.