1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 99Get this manual
3Anti-Siphon Valvesafety standards require permanently installed fuel systems to have anti-siphon protectionThis protection can be afforded in two ways All fuel distribution lines must be secured above the highest fuel level when the boat is in its normal, unloaded, static floating position Each fuel pickup tube must have an anti-siphon valve installedAnti -siphon valves used must have pressure drop of no more than 2.5 in of mercury (Hg) at flow rate of 20 gallons per hourThe following OMC valves meet this requirement: PIN 173273 for 5 16 in1.0hose PIN 173274 for 38 in 1.0hose PIN 173275 for 38 in 0.0copper Fuel Distribution linesminimum inside diameter of 38 in (9,5 mm) is required for engines above 200 HP3 in (9,5 mm) is preferred for engines below 200 HP, while minimum of 516 in(7,9 mm) is required Distribution lines must be USCG Type "A" reinforced neopreneVinyl hose must not be used in permanently installed fuel distribution system 5Fuel Distribution Fittingsall fittings must have minimum inside diameter of 114 in(6,4 mm), while 932 in(7,1 mm) is preferred6Fuel Filterfuel filters must have pressure drop of no more than 0.4 inof mercury (Hg) at flow rate of 20 gallons per hourThe filter should have minimum filtered area of 200 square inches (1290 cm )OMC Fuel Filter Kit PIN 174176 meets these requirements7 Fuel System PrimingOMC Electric Fuel Primer Kit PIN 395251 is available for built-in fuel systemsThe kit mounts near the fuel supply and, when activated, fills the fuel distribution lines and engine fuel system for quicker startingOMC Manual Filter Primer Assembly PIN 377381 is available for engines below 120 HP 45C