1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 98Get this manual
Boat Fuel System Recommendations Purpose This information is provided to assist you in evaluating boat's permanently installed fuel system Large outboards require boat fuel system that has high fuel flow rate and low pressure drop across the entire systemIt is very important that all boat fuel system components are of the correct capacity and that they are properly installedABYC's Standard H-24 and ICOMIA's Standard No17 are accepted as industry standards and should be referred to for additional information
INote installed fuel syst.e,m withexcessiye restrictions could exceed the VRO Unit pumping capacity
and cause poor engine performance or serious powerhead damageTo evaluate the restrictiveness of permanently installed fuel system, refer to Testing Fuel System, this Section Recommendations 1Fuel Tank Pickup Tubeminimum inside diameter of 3 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 Two separate pickup tubes are required for dual engine installation