F715061 1 Force CARBURETOR (FO-1B)

Fuel System Inspection
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 or a bad bend.3. Install a new fuel filter. Clean the primary fuel filter.4. To remove air from the fuel system, use the procedure that follows:PC Engines:
a. Use the priming pump to remove air from the low pressure side of the fuel system.b. Loosen (one at a time) the fuel injection line nut one-half turn at the valve cover base adapter. Use the priming pump until fuel without air flows from the loose connections, then tighten the nut. Repeat the procedure for each fuel injection line.DI Engines:
a. Use the priming pump to remove air from the low pressure side of the fuel system.b. Loosen one-half turn the fuel injection line nuts at each adapter in the valve cover base. Move governor control shaft to LOW IDLE position. Use the starter motor to turn the engine until fuel without air flows from the loose connections. Tighten the nuts. Because of the check assemblies in the injection pump outlets for the DI engine, the priming pump will not give enough pressure to remove air from the fuel injection lines.5. Inspect the fuel bypass valve to see that there is no restriction to good operation.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 injection valve for that cylinder.Temperature of an exhaust manifold port, when the engine runs at low idle speed, can also be an indication of the condition of a fuel injection valve. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This can possibly be an indication of an injection valve 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 an injection valve with a defect.The most common defects found with the fuel injection valves are:1. Steel wire brushing of nozzle tip.2. Orifice wear.Testing Capsule-Type Fuel Injection Nozzles
5P4150 Nozzle Testing Group 5P4720 Fitting5P8744 Adapter or5P4717 Adapter8S2270 Fuel CollectorFT1384 Extension8S2245 Cleaning Kit6V6068 Calibration Fluid 19 liters (5 U.S. gal.) or6V6067 Calibration Fluid 208 liters (55 U.S. gal.)
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.
For more information on the 5P4150 Nozzle Testing Group see, Special Instruction Form No. SEHS7292.
5P4150 Nozzle Testing Group
(A) 5P4721 Tube. (B) 5P4146 Gauge, 0 to 6900 kPa (0 to 1000 psi) used to test PC capsule-type nozzles. (C) 2P2324 Gauge, 0 to 34 500 kPa (0 to 5000 psi) used to test DI capsule-type nozzles and pencil-type nozzles. (D) Gauge protector valve for 5P4146 Gauge (B). (E) Gauge protector valve for 2P2324 Gauge (C). (F) On-off valve. (G) Pump isolator valve. (H) 5P4720 Fitting. (J) 5P8744 Adapter for capsule-type nozzles. (K) 5P4244 Adapter for pencil-type nozzles.
Extra Valve
(L) Gauge protector valve (must be in open position at all times).
When fuel injection nozzles are tested, be sure to wear eye protection. Test fluid comes from the orifices in the nozzle tip with high pressure. The test fluid can pierce (go through) the skin and cause serious injury to the operator. Keep the tip of the nozzle pointed away from the operator and into the 8S2270 Fuel Collector and FT1384 Extension.
The test procedures that follow will give an indication of nozzle condition. A nozzle that has a defect is not always the only cause for a specific engine problem.Nozzle Tester Preparation
Find an old capsule-type fuel nozzle and weld the orifice closed. Keep this fuel nozzle with the tester group for use in the future. Do not weld the fuel nozzles that are to be tested.
Illustration I
(1) Test nozzle (welded orifice). (2) Bottom part of 5P8744 Adapter (J). (J) 5P8744 Adapter. (M) FT1384 Extension. (N) 8S2270 Collector.Illustration I shows the latest 5P8744 Adapter. Illustration II shows the former 5P4717 Adapter. Unless some indication is made, the procedure is the same for use of either adapter.
Illustration II
(1) Test nozzle (welded orifice). (2) Bottom part of 5P4717 Adapter (J). (J) 5P4717 Adapter.1. Install the top part of adapter (J) that holds the capsule nozzle.2. Put test nozzle (1) (with welded orifice) in the bottom part (2) of adapter (J) that holds the capsule nozzle. Install and tighten bottom part (2) to top part of adapter (J).3. Close on-off valve (F). Open pump isolator valve (G). Open gauge protector valve (E).4. Operate the tester pump until a pressure of 24 000 kPa (3500 psi) is read on 2P2324 Gauge (C). Now, close pump isolator valve (G).5. Check all connections for leaks. Tighten connections to stop any leaks that are found.6. Open on-off valve (F) and remove test (welded) fuel nozzle (1).
Do not loosen the bottom half of the adapter to remove fuel nozzle until on-off valve is opened and no pressure is read on the gauge. Unless high pressure is released in the pump, the