FPS625 Force PROPELLER (13 X 19)

Fuel System Inspection
To check for low fuel pressure, remove the 1/8" Pipe Plug from the fuel filter base. Connect a pressure gauge from the 1U5470 Engine Pressure Group to the hole where the plug was removed. Run the engine at high idle and check the fuel pressure reading. The fuel pressure must be at least 158 kpa (23 psi).A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.1. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.2. Check the fuel lines for fuel leakage. Be sure the fuel supply line does not have a restriction.3. Install a new fuel filter. Clean the primary fuel filter.4. Remove any air that may be in the fuel system. If there is air in the fuel system, use the priming pump and open the drain valve on the fuel injection pump housing until fuel without air comes from the drain line.
When fuel injection lines are loosened or tightened on the fuel injection nozzles, two wrenches must be used. The nozzle must be held with a wrench or damage to the nozzle can result.
To remove air from the fuel injection lines, loosen the fuel line nuts on the fuel injection nozzles 1/2 turn. Move the governor lever to the low idle position. Crank engine with the starting motor until fuel without air comes from the fuel line connections. Tighten the fuel line nuts. The fuel priming pump will not give enough pressure to push fuel through the reverse flow check valves in the fuel injection pumps.Checking Engine Cylinders Separately
An easy check can be made to find the cylinder that runs rough (misfires) and causes black smoke to come out of the exhaust pipe.Run the engine at the speed that is the roughest. Loosen the fuel line nut at a fuel injection pump. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes no difference in engine performance. Be sure to tighten each fuel line nut after the test before the next fuel line nut is loosened. Check each cylinder by this method. When a cylinder is found where the loosened fuel line nut does not make a difference in engine performance, test the injection pump and fuel injection nozzle for that cylinder.Temperature of an exhaust manifold port, when an engine runs at low idle speed, can also be an indication of the condition of a fuel injection nozzle. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This can possibly be an indication of a nozzle with a defect. Extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder, also caused by a nozzle with a defect.The most common defects found with the fuel injection nozzles are:1. Carbon on tip of the nozzle or in the nozzle orifice.2. Orifice wear.3. Steel wire brushing of nozzle tip.Testing Fuel Injection Nozzles
For more information on the 5P5140 Nozzle Testing Group see, Special Instruction, Form No. SEHS7292.
Be sure to use clean SAE J967 Calibration Fluid when tests are made. Dirty test fluid will damage components of fuel injection nozzles. The temperature of the test fluid must be 18 to 24°C (65 to 75°F) for good test results.
Do not test nozzles unless you have the correct service tools.
5P4150 Nozzle Testing Group
(1) 8N7005 Nozzle Assembly. (A) 5P7448 Adapter. (B) 5P4146 Gauge, 0 to 6900 kPa (0 to 1000 psi). (C) 6V2170 Tube Assembly. (D) 2P2324 Gauge, 0 to 34 500 kPa (0 to 5000 psi). (E) Gauge protector valve for 2P2324 Gauge. (F) FT1384 Extension. (G) Gauge protector valve for 5P4146 Gauge. (H) On-off valve. (J) 8S2270 Fuel Collector. (K) Pump isolator valve.
Extra Valve
(L) Gauge protector valve (must be in open position at all times).The fuel injection nozzle is not to be disassembled for cleaning or adjustment. Do the tests that follow to determine if the nozzle performance is acceptable.Valve Opening Pressure Test.Flush the Nozzle.Tip Leakage Test.Orifice Restriction Test.Bleedscrew Leakage Test.Nozzle Preparation for Test
Before fuel injection nozzle (1) can be tested, all loose carbon around the tip of the nozzle must be removed with the 8S2258 Brass Wire Brush (M).
Removing Carbon Dam
(1) Fuel injection nozzle. (2) Carbon dam. (3) Seal.Remove carbon dam (2) with needle nose pliers and remove seal (3) from the nozzle.
Do not use a steel brush or a wire wheel to clean the nozzle body or the nozzle tip. Use of these tools can cause a small reduction of orifice size, and this will cause a large reduction in engine horsepower. Too much use of the 8S2258 Brass Wire Brush will also remove the coating that is on the nozzle for protection.
Clean the groove for carbon seal dam (2) and the body of the nozzle below the groove with the 8S2258 Brass Wire Brush (M). Remove the carbon, but be sure not to use the brush enough to cause damage to the body of the nozzle. A change in color in the area below the groove is normal and does not effect the body of the nozzle.
8S2245 Cleaning Kit
(M) 8S2258 Brass Wire Brush. (N) 6V4979 Carbon Seal Tool. (P) 8S2250 Nozzle Holding Tool.
Fuel Injection Nozzle
(4) Bleed screw and seal.Remove bleed screw and seal (4) from the nozzle. The bleed screw and seal must be removed for all tests except the Bleed Screw Leakage Test.Valve Opening Pressure Test (VOP)
1. Install 6V2170 Tube Assembly (C) to the tester.2. Install fuel injection nozzle with 5P7448 Adapter (A) on tube assembly (6). Position the bleed screw hole toward the tester and in line with 6V2170 Tube Assembly (C). This will make the fuel spray pattern horizontal. Be sure the nozzle tip is down and extends into FT1384 Extension (F) and 8S2270 Fuel Collector (J).
When fuel injection nozzles are tested, be sure to