106684-4421 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1066844421

Engine Description
Older 3408 and 3412 models may by precombustion chamber (PC) type engines. Newer 3408 and 3412 models are direct injection (DI) engines.A mechanical governor controls the fuel injection pump output to maintain the engine rpm selected by the operator. The fuel injection pump meters and pumps fuel under high pressure to a fuel injection nozzle for each cylinder. An automatic timing device advances or retards fuel injection to provide the best fuel injection timing over the full range of engine speed.The air/fuel ratio control, located on the governor, restricts the movement of the fuel rack, allowing only the proper amount of fuel to be injected into the cylinders during acceleration, to minimize exhaust smoke.These engines are available as turbocharged (T) or turbocharged and aftercooled (TA). Inlet air is filtered by an air cleaner before entering the engine cylinders. In turbocharged engines, the filtered inlet air is compressed by a turbocharger before entering the engine cylinders. The turbocharger is driven by the engine exhaust.There are four in-head valves (two inlet valves and two exhaust valves) for each cylinder. The camshaft actuates the rocker arms and the valves through mechanical lifters and push rods.The jacket water cooling system uses an expansion tank and a gear driven centrifugal water pump. The engine coolant is circulated by passing through the oil cooler first, then to the engine block and cylinder head. One water temperature regulator for each cylinder bank regulates engine coolant temperature by restricting coolant flow for quick engine warm-up. The regulator opens to allow free circulation of coolant after operating temperature has been reached.The watercooled exhaust manifolds, risers and turbochargers are designed to minimize radiated heat in the engine room.Lubrication of the engine is accomplished by a gear-type pump and bypass valves. The pump provides full pressure lubrication to the engine internal and external parts. The engine lubricating oil (both cooled and filtered) provides unrestricted flow to engine parts when oil viscosity is high or if the oil cooler is restricted or if the oil filter elements become plugged.The engines are available with SAE standard counterclockwise rotation (CCW when viewed from rear of engine). The engines can be equipped with either the SAE No.1 flywheel or the SAE No.0 flywheel to mate with various marine gears. Several marine gear manufacturers offer marine transmissions for the engines through local distributors.Engine Specifications
3408 Engine
3412 Engine