1995 Johnson/Evinrude Outboards 50 thru 70 3-cylinder Service Manual, Page 61Get this manual
Boat Fuel System Recommendations Purpose This information is provided to assist you in evaluating boat's permanently installed fuel systemLarge 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 No.17 are accepted as industry standards and should be referred to for additional information
INote permanently installed fuel system with excessive restrictions could exceed the unit's 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 SectionRecommendations 1Fuel Tank Pickup Tubeminimum inside diameter of 38 in(9,5 mm) is required for V6 and larger enginesA minimum of 516 in(7,9 mm) is required for V4 and smaller engines, but 3 in(9,5 mm) inside diameter is preferredOne pickup tube per enging is required in mUlti-engine installations