16730-ZY3-A02 Honda SEE PART DETAILS - SUP; SEPARATOR ASSY., VAPOR

Engine Design
Cylinder, Valve And Injection Pump LocationBore ... 137.2 mm (5.40 in)Stroke ... 152.4 mm (6.00 in)Number and Arrangement of Cylinders ... V-8Firing Order (Injection Sequence) ... 1, 8, 4, 3, 6, 5, 7, 2Rotation of Crankshaft (when seen from flywheel end) ... counterclockwiseRotation of Fuel Pump Camshaft (when seen from pump drive end) ... counterclockwise Front end of engine is opposite to flywheel end.Left side and right side of engine are as seen from flywheel end.No. 1 cylinder is the front cylinder on the left side.No. 2 cylinder is the front cylinder on the right side.Fuel System
This engine has a pressure type fuel system. There is one injection pump and injection valve for each cylinder. The injection pumps are in the pump housing (3) on top front of the engine. The injection valves are in the adapters under the valve covers.The transfer pump (8) pulls fuel from the fuel tank (5) through the primary filter (7) and sends it through the priming pump (9), main filter (10) and to the manifold of the injection pump housing. The fuel in the manifold of the injection pump housing goes to the injection pumps. The injection pumps are in time with the engine and send fuel to the injection valves under high pressure.
Fuel System Schematic
(1) Fuel inlet line for the injection pump housing. (2) Adapter with orifice. (3) Injection pump housing. (4) Fuel return line. (5) Fuel tank. (6) Fuel supply lines. (7) Primary fuel filter. (8) Fuel transfer pump. (9) Fuel priming pump. (10) Main fuel filter.Some of the fuel in the manifold is constantly sent back through the return line (4) to the fuel tank to remove air from the system and to help cool the fuel in the injection pump housing. On the outlet elbow of the injection pump there is a restriction orifice (2) to keep fuel pressure high and to control the amount of fuel that goes back to the fuel tank.The priming pump (9) is used to fill the system with fuel and to remove air from the fuel filter, fuel lines and components.The transfer pump has a bypass valve and a check valve. The bypass valve (lower side) controls the maximum pressure of the fuel. The extra fuel goes to the inlet of the pump. The check valve lets fuel from the tank go past the transfer pump gears when the priming pump is used.
Location of Fuel System Components
(1) Inlet line. (2) Adapter with orifice. (3) Injection pump housing. (4) Fuel return line.There is no bleed orifice or valve installed on the fuel injection pump housing to vent air from this part of the fuel system. Air trapped in the fuel injection lines can be vented by loosening all of the fuel injection line nuts where they connect to the adapters in the valve cover base. Move the governor lever to the low idle position. Crank the engine with the starter motor until fuel without air comes from the fuel line connections. Tighten the fuel line nuts. This procedure is necessary because the fuel priming pump will not give enough pressure to push fuel through the reverse flow check valves in the fuel injection pumps of a direct injection system.An automatic timing advance unit is mounted on the front of the fuel injection pump camshaft. It is driven by the engine camshaft gear inside the front timing gear housing. The automatic timing advance unit gives easier starting and smooth low speed operation. It will also advance timing as engine speed increases to give correct engine operating efficiency.Fuel Injection Pump
The rotation of the cams on the camshaft (12) cause lifters (9) and pump plungers (5) to move up and down. The stroke of each pump plunger is always the same. The force of springs (6) hold lifters (9) against the cams of the camshaft.The pump housing is a "V" shape (similar to the engine cylinder block), with four pumps on each side.When the pump plunger is down, fuel from fuel manifold (1) goes through inlet passage (2) and fills the chamber above pump plunger (5). As the plunger moves up it closes the inlet passage.The pressure of the fuel in the chamber above the plunger increases until it is high enough to cause check valve (3) to open. Fuel under high pressure flows out of the check valve, through the fuel line to the injection valve, until the inlet passage opens into pressure relief passage (4) in the plunger. The pressure in the chamber decreases and check valve (3) closes.The longer inlet passage (2) is closed, the larger the amount of fuel which will be forced through check valve (3). The period for which the inlet passage is closed is controlled by pressure relief passage (4). The design of the passage makes it possible to change the inlet pasage closed time by rotation of the plunger. When the governor moves fuel racks (8), they move gears (7) that are fastened to plungers (5). This causes a rotation of the plungers.
Cross Section Of The Fuel Injection Pump Housing
(1) Fuel manifold. (2) Inlet passage. (3) Check valve. (4) Pressure relief passage. (5) Pump plunger. (6) Spring. (7) Gear. (8) Fuel rack (left). (9) Lifter. (10) Link. (11) Lever. (12) Camshaft.The governor is connected to the left rack. The spring load on lever (11) removes the play between the racks and link (10). The fuel racks are connected by link (10). They move in opposite directions (when one rack moves in, the other rack moves out).Fuel Injection Valves (Nozzles) (On Earlier Engines)
The fuel injection nozzles are installed in the precombustion chambers in engines equipped with precombustion chambers. An adapter takes the place of the precombustion chamber in engines equipped with direct injection. The precombustion chambers or adapters are installed in the cylinder heads.Fuel, under high pressure from the injection pump, is sent through the fuel injection line to the injection valve in the nozzle. The injection valve will not open until the fuel in the injection lines