1998 Johnson Evinrude "EC" 25, 35 HP 3-Cylinder Outboards Service Manual, Page 62Get 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 inches Hg at flow rate of 20 gallons per hourThe following OMC valves meet this requirement: PIN 173273 for PI 173274 for PIN 173275 for 516
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4Fuel Distribution Linesminimum inside diameter of 3S in(9,5 mml is required for V6 and larger engines3fa in(9,5 mml is preferred for V4 and smaller engines, while minimum of 5116 in(7,9 mml is requiredDistribution lines must be USCG Type "A 1" or "81"Vinyl hose must not be used in permanently installed fuel distribution system5Fuel Distribution Fittingsall fittings must have minimum inside diameter of 14 in(6,4 mml, while 9132 in(7,1 mml is preferred 6Fuel Filterfuel filters must have pressure drop of no more than 0.4 inch Hg at flow rate of 20 gallons per hourThe filter should have minimum filtered area of 200 square inches (1290 cm 21OMC Fuel Filter Kit, PI 174176, meets these requirements7Fuel System PrimingOMC Electric Fuel Primer Kit, PIN 174651, 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, PI 398540, is available for engines below 120 HP