5040272 EVINRUDE NEUTRAL LOCK ARM

Power Take-Off Clutches
Power Take-Off Clutch (Typical Illustration)
(1) Ring (2) Driven discs (3) Link assemblies (4) Lever (5) Key (6) Collar assembly (7) Nut (8) Yoke assembly (9) Hub (10) Plates (11) Output shaftPower take-off clutches (PTO's) are used to send power from the engine to accessory components. For example, a PTO can be used to drive an air compressor or a water pump.The PTO is driven by a ring (1) that has spline teeth around the inside diameter. The ring can be connected to the front or rear of the engine crankshaft by an adapter. On some PTO's located at the rear of the engine, ring (1) is a part of the flywheel.The spline teeth on the ring engage with the spline teeth on the outside diameter of driven discs (2). When lever (4) is moved to the ENGAGED position, yoke assembly (8) moves collar assembly (6) in the direction of the engine. The collar assembly is connected to four link assemblies (3). The action of the link assemblies will hold the faces of driven discs (2), drive plates (10) and hub (9) tight together. Friction between these faces permits the flow of torque from ring (1), through driven discs (2), to plates (10) and hub (9). Spline teeth on the inside diameter of the plates drive the hub. The hub is held in position on the output shaft (11) by a taper, nut (7) and key (5). A PTO can have from one to three driven discs (2) with a respective number of plates.When lever (4) is moved to the NOT ENGAGED position, yoke assembly (8) moves collar assembly (6) to the left. The movement of the collar assembly will release link assemblies (3). With the link assemblies released there will not be enough friction between the faces of the clutch assembly to permit a flow of torque.Electrical System
Three electrical systems are available to provide engine protection. In each case, engine shutoff is achieved by grounding the magneto. Each system is also capable of activating the gas shutoff valve if provided.1. For the self-powered protection system, oil pressure (OP) and water temperature (WT) protection are provided. When combined with a mechanical overspeed contactor switch (MOS), full protection is obtained. An energized-to-shutoff (ETS) gas shutoff valve (GSOV) is available which is activated by magneto voltage.2. An energized-to-run (ETR) non-auto-start-stop protection system provides OP, WT and OS (overspeed) protection. An electronic speed switch (ESS) is used for the OS protection. This system is fully independent and requires an external 24 volt power source and an energized-to-run (ETR) gas shut-off valve.3. The ETR auto-start-stop protection system is the same as system #2 above except it is not fully independent. An auto start-stop cranking panel must be wired into the system (by the customer) to provide starting and stopping logic.Electrical Schematics And Wiring Diagrams
Electrical schematic foldouts are provided in this section with the text for each protection system. Use the electrical schematics to follow the circuit operations of the protection systems.Point-to-point wiring diagrams for the protection systems, junction boxes, and starting, charging, and tachometer circuits are located in the Wiring Diagrams Section of this module. Use the diagrams for component position layout.Components
The components that follow may be used on one or more of the three protection systems available on the 3408 and 3412 spark ignited engines.Water Temperature Sending Unit (WTSU)
Sending Unit for Water Temperature
(1) Connection (2) Bushing (3) BulbThe sending unit for water temperature is an electrical resistance. It changes the value of its resistance according to the temperature which the bulb (3) feels.The sending unit is in a series circuit with the electrical gauge. When the temperature is high, the resistance is high. This makes the gauge have a high reading.The sending unit must be in contact with the coolant. If the coolant level is too low because of a sudden loss of coolant while the engine is running or because the level is too low before starting the engine, the sending unit will not work correctly.This sending unit requires 24VDC electrical input, therefore, it is only used with the energized-to-run protection systems.Oil Pressure Sending Unit (OPSU)
Sending Unit for Oil Pressure (Typical Example)
(1) Connection (2) FittingThe sending unit for oil pressure is an electrical, resistance. It has a material which changes electrical resistance according to pressure which it feels.The sending unit for oil pressure is in a series circuit with the electrical gauge. As the pressure on the sending unit changes, the reading on the gauge changes in the same way.This sending unit requires 24VDC electrical input, therefore, it is only used with the energized-to-run protection systems.Electric Service Meter
The electric service meter group is self-powered. A magnetic pickup mounted on the flywheel housing provides voltage (starting at 200 engine rpm) to power the electric service meter which records clock hours with quartz accuracy. A separate magnetic pickup must be used for each service meter; it cannot be shared with the digital tachometer, electronic speed switch, or electronic governor magnetic pickup.Water Temperature Contactor Switch (WTS)
A water temperature contactor switch is located in the cooling system. The unit is nonadjustable. Thermal expansion of the element operates a micro-switch that signals the shutoff solenoid which causes engine shutdown. The water temperature element must be in contact with the coolant. If overheating occurs due to low coolant level or not coolant, the sending unit will not function.The water temperature sending unit can also be wired into an alarm system or light to signal high water temperature. After an overheated engine is allowed to cool, the contactor automatically resets itself.
Contactor Switch (Water Temperature)Magnetic Pickup (MPU)
Magnetic Pickup
(1) Clearance dimension (2) Magnetic pickup (3) Wires (4) Locknut (5) Gear tooth (6) HousingThe magnetic pickup is a single pole, permanent magnet generator made of wire coils around a permanent magnet pole piece. As the teeth of the flywheel ring gear go through the magnetic lines of force around the pickup, an AC voltage is made. A positive voltage is made when each tooth goes by the pole piece.