Fuel Delivery System - FNM HPEP 225 Installation Manual

Fuel Delivery System

WARNING
Boating standards (CEE) and Coast Guard regulations must be adhered to when installing
fuel delivery system.
GENERAL
The main concern of a boat's fuel system is safety; this must be achieved through a technically sound
installation and constant inspection.
The fuel system, from the filler pipe to the fuel pump is the same, in principle, for all boats.
The Fuel Tank is an integrated component of the boat. Refer to the special information on service and
maintenance from the tank manufacturer.
Only a few points related to function and safety are listed here.
• All connections should be on the upper side of the tank.
• The drain plug at the lowest point on the tank serves to permit the removal of water and
sediment.
• The filler pipe outer diameter should be at least 2 in. (50 mm).
• The tank breather pipe must have an inner diameter (I.D.) of at least 1/2 in. (13 mm) and
must be fitted with a swan neck to prevent water from entering the tank.
It is recommended that the exact route and length of the fuel lines be established at the first installation of
the engine to prevent problems later in connecting them to the engine.
All fuel lines must be well secured. The holes where the lines run through the bulkheads should be
carefully rounded off, or protected with rubber grommets. This prevents damage to the lines from
abrasion.
FUEL CONNECTIONS
The following, but not limited to the following, additional fuel connection related points, applying to
all engines unless otherwise stated, must be considered.
1. Fuel pickup should be at least 1 in. (25 mm) from the bottom of fuel tank, to prevent
picking up impurities.
2. Fuel inlet fitting is an 8 mm (5/16 in.) barbed fitting attached to the fuel supply pump.
3. A flexible fuel line must be used to connect fuel supply line to fuel inlet fitting on the
engine to absorb deflection when engine is running. Injection pump fuel return line must
also have a flexible rubber hose segment.
4. Fuel supply lines must not be smaller than 5/16 in. (8 mm) I.D. tube. A fuel return line
between engine and fuel tank is required, having the same size I.D. as the supply line.
5. On Multi-Engine Diesel Installations: Use a separate tube for the fuel supply line and
fuel return line, for each engine.
6. Larger diameter (than previously specified) lines and fittings must be used on
installations requiring long lines or numerous fittings.
7. Fuel line(s) should be installed free of stress and firmly secured to prevent vibration
and/or chafing.
8. Sharp bends in fuel lines should be avoided.
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