N38143 Chapter 3 Fuel systems 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.
It is strongly recommended that the flexible fuel pipes available as an option with the engine are used, which are as follows: Fuel connections - 415GM, 422GM, 422TGM & 700GM Standard Fuel Feed The free end of the flexible fuel pipe has either: 1/4” BSP male thread. Standard Fuel Return The free end of the flexible pipe has either: a 1/4” BSP male thread. Optional Fuel Feed The free end of the flexible fuel pipe has either: 1/4” BSP male thread. Optional Fuel Return The free end of the flexible pipe has either: a 1/4” BSP male thread. Caution: Ensure that flexible fuel hose routing avoids coming into contact with parts of the engine which can lead to abrasion of the hose.
Fuel connections - 4GM, 4TGM 4.4GM, 4.4TGM, 4.4TWGM, 4.4TW2GM, 6TG2AM & 6TWGM Standard Fuel Feed 5/16” OD, nut and olive to suit 5/16” OD steel or copper tube. Standard Fuel Return a 1/4” OD, nut and olive to suit 1/4” OD steel or copper tube. Optional Fuel Feed 5/16” BSP male thread, nut and olive to suit 5/16” OD steel or copper tube. Optional Fuel Return a 1/4” BSP male thread, nut and olive to suit 1/4” OD steel or copper tube. Caution: Ensure that flexible fuel hose routing avoids coming into contact with parts of the engine which can lead to abrasion of the hose. Page 11