N40475 Chapter 7 Fuel systems Cleanliness of fuel system components Cleanliness of the engine NOTICE It is important to maintain extreme cleanliness when working on the fuel system, since even tiny particles can cause engine or fuel system problems. Ensure the external surfaces of the engine are clean and dry before commencing work. Remove dirt and loose debris before starting a repair on the fuel system. Ensure that no high pressure water is directed at the seals for the injectors. Environment When possible, the service area should be positively pressurised with a clean air supply in order to ensure that the components are not exposed to contamination from airborne dirt and debris.
When a component is removed from the system, the exposed fuel connections must be closed off immediately with suitable sealing plugs. The sealing plugs should only be removed when the component is reconnected. The sealing plugs must not be reused. Dispose of the sealing plugs immediately after use. Contact your nearest Perkins distributor in order to obtain the correct sealing plugs. New components High pressure fuel lines are not reusable. New high pressure lines are manufactured for installation in one position only. When a high pressure line is replaced, do not bend or distort the new line. Internal damage to the pipe may cause metallic particles to be introduced to the fuel.
All new fuel filters, high pressure lines, tube assemblies and components are supplied with sealing plugs. These sealing plugs should only be removed in order to install the new part. If the new component is not supplied with sealing plugs then the component should not be used. The technician must wear suitable rubber gloves. The rubber gloves should be disposed of immediately after completion of the repair in order to prevent contamination of the system. Refuelling In order to refuel the diesel fuel tank, the refuelling pump and the fuel tank cap assembly must be clean and free from dirt and debris.
Only use fuel, free from contamination, that conforms to the specifications in the Users Handbook. Design and assembly faults in the fuel system are responsible for many problems with marine diesel engines. A good system is not hard to achieve, being largely a matter of avoiding obvious pitfalls. Fuel connections A common reason for service problems with fuel systems is the use of poor or incompatible connectors, where the pressure tightness depends upon the use of sealing compounds, hose clamps, fibre washers trapped between inadequate and unmachined faces, or compression fittings which have been over-tightened to the point where they no longer seal.
Cleanliness during initial assembly is also of vital importance, particularly when fuel tanks are installed, as glass fibres and other rubbish may enter tanks through uncovered apertures. Page 19