SCHEMATIC OF FUEL SYSTEM
1. Constant bleed valve. 2. Disc. 3. Siphon break orifice. 4. Priming pump. 5. Fuel injection pump. 6. Fuel injection valve. 7. Bleed valve. 8. Fuel return line. 9. Fuel supply line [optional water separator (W.S.) installation is shown by dash lines]. 10. Fuel tank. 11. Fuel filter. 12. Channel. 13. Check valve. 14. Check valve. 15. Housing for the fuel injection pumps. 16. Check valve. 17. Bypass valve. 18. Transfer pump.
When the priming pump handle is pulled out, negative air pressure in the pump makes check valve (13) open and pulls fuel from the tank. Pushing the handle in closes check valve (13) and opens check valve (14). This pushes air and/or fuel into the housing through passage (35) and check valve (16). More operation of the priming pump will pull fuel from the tank until fuel supply line (9), fuel filter (11) and housing (15) are full of fuel. At this time the fuel flow from the bleed valve (7) will have no air bubbles.