GENERAL SERVICE INFORMATION
3-10
BY Service Manual
Diesel Fuel
DIESEL FUEL
Diesel Fuel Specifications
Diesel fuel should comply with the following
specifications. The table lists several specifications
for diesel fuels.
Additional Technical Fuel Requirements
• The fuel cetane number should be equal to 48 or
higher.
• The sulfur content must not exceed 0.3% by
volume. Less than 0.05% is preferred.
• Water and sediment in the fuel should not exceed
0.05% by volume.
• Ash content not to exceed 0.01% by mass.
• Carbon residue content not to exceed 0.35% by
volume. Less than 0.1% is preferred.
• Total aromatics content should not exceed 35%
by volume. Less than 30% is preferred.
• PAH (polycyclic aromatic hydrocarbons) content
should be below 10% by volume.
• NEVER mix kerosene, used engine oil, or
residual fuels with the diesel fuel.
• NEVER use Biocide or mix winter and summer
fuels.
• Keep the fuel tank and fuel-handling equipment
clean at all times.
• Poor quality fuel can reduce engine performance
and / or cause engine damage.
• Fuel additives are not recommended. Some fuel
additives may cause poor engine performance.
Diesel Fuel Lines
Figure 3-9
1 – Optional Boatbuilder Installed Fuel Filter /
Water Separator (30 Micron Pre-Filter)
2 – Fuel to Fuel Feed Pump
3 – Less than 500 mm (19.68 in.)
4 – Fuel Return Line
5 – Fuel Tank
6 – Fuel Tank Drain Cock
7 – Approximately 20 - 30 mm (0.75 - 1.125 in.)
8 – Fuel Shutoff Valve
IMPORTANT
The fuel supply line between the fuel tank
and engine must be at least 8 mm
(0.315 in.) in diameter.
Shown is a typical installation of a boat fuel system.
Fuel supply (Figure 3-9, (2)) and return
(Figure 3-9, (4)) lines connect to fittings at the
engine.
Install a drain cock (Figure 3-9, (6)) at the bottom
of the fuel tank to remove water and contaminants.
Yanmar recommends a 30 micron fuel filter / water
separator (pre-filter) (Figure 3-9, (1)) be installed
between the fuel tank and the fuel connection point
on the engine.
Boat fuel supply system restriction must not exceed
1000 mmAq (39.37 in.Aq)
Boat fuel return system restriction must not exceed
200 mmAq (7.87 in.Aq)
DIESEL FUEL
SPECIFICATION
LOCATION
No. 2-D, No. 1-D,
ASTM D975-94
USA
EN590:96 European Union
0003638
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(1) (4)
(6)
(8)
(5)
(7)
(3)
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