0306697 EVINRUDE SCREW, Gearcase to hsg. long

Illustration 1 g03383792The cylinder block is the main housing of the engine and supports the other main parts. The cylinder block is a tunnel block design. The cylinder block is made of cast iron and includes complete passages for coolant and lubricating oil.Note: These engines do not have cylinder liners. The cylinder walls are honed.
Illustration 2 g02789553The cylinder block has a hollow core already cast inside the cylinder to cylinder water jacket.In this core, there is a pair of vertical cooling passages (right and left) as well as multiple horizontal cooling channels that interconnect these cooling passages. This design allows smoother cooling water flow through the cylinder block, which cools down a wider range between the cylinders more effectively.Half-Floating Valve Cover
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(1) Valve Cover
(2) Rubber Packing The rubber packing is attached to keep the cylinder head cover approximately 0.5 mm (0.02 inch) off the cylinder head. The rubber packing decreases the noise from the cylinder head.Closed Crankcase Breather
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(3) Breather
(4) Breather Tube
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(5) Breather Valve
(6) Oil Shield Closed breather system has been adopted to prevent the release of blow-by gas into the atmosphere.After the oil content is filtered by oil shield (6), the blow-by gas is fed back to the intake manifold through breather valve (5) to be used for combustion.Crankshaft
Illustration 6 g02792771The crankshaft converts the up-and-down motion of the pistons into rotary motion. The crankshaft ties together the reactions of all the pistons into one rotary force that drives the machine.The crankshaft is made of tough special alloy steel, and the journals, pins, and oil seal sliding portions are induction hardened to increase the hardness for higher wear resistance.The front journal is supported by a solid type bearing (tunnel type cylinder block) or by a split type (hanger type cylinder block), and the intermediate journal by a split type, and the rear journal by a split type with thrust bearings.The crankshaft is provided with an oil gallery, through which engine oil is fed to the crankpin portion, and lubricates.Camshaft
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(7) Camshaft Gear
(8) Camshaft The camshaft (8) is normally driven by gearing from the crankshaft (7).The camshaft is made of special cast iron, and the journal and cam sections are chilled to resist wear. One intake and one exhaust cam is provided for each cylinder.Note: On some models, the camshaft may also drive oil pump using a gear.The journal diameters are large to permit removal of the shaft from the bore. The journal sections are force-lubricated.Note: There are no camshaft bearings for these engines.Timing Gears
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(9) Injection Pump GearGovernor Gear
(10) Idler Gear
(11) Camshaft Gear
(12) Crankshaft Gear
(13) Oil pump drive gear The crankshaft is the hub around which other parts of the engine can be timed and driven. This is done by the meshing of gears as shown in the Illustration 8.The timing gears transmit torque from the crankshaft to the oil pump and injection pump and, at the same time, correctly control fuel injection to the cylinders and valve timing.Each gear has a mating mark inscribed on the gear for correct and easy assembly and is spherical with teeth set obliquely to the axis of rotation to rotate smoothly and reduce noise.Flywheel
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(14) Crankshaft
(15) Flywheel Ring Gear
(16) Flywheel The flywheel (16) is made of heavy cast iron or steel and has gear teeth around the outer rim (15), which mesh with the drive pinion of starter.The flywheel mounted on the rear of the crankshaft (14) is a stabilizer for the whole engine.The flywheel stores the rotating force in the combustion stroke as inertial energy, reduces crankshaft rotating speed fluctuation and maintains the smooth rotating conditions.The flywheel periphery is inscribed with the marks showing fuel injection timing angle lines and top dead center mark "TC" for 1# piston.Rocker Arm