Perkins M92B - Engine Fluids; Fuel Specification

N37347 Chapter 5
Page 41
Engine uids
Fuel specication
To get the correct power and performance from your engine, use good quality fuel. The recommended fuel
specication for Perkins engines is indicated below:
Cetane number: 45 minimum
Viscosity: 2.5/4.5 centistokes at 40
O
C
Density: 0,835/0,855 kg/litre
Sulphur: 0.2% of mass, maximum
Distillation: 85% at 350
O
C
Cetane number indicates ignition performance. A fuel with a low cetane number can cause cold start problems
and affect combustion.
Viscosity is the resistance to ow and engine performance can be affected if it is outside the limits.
Density: A lower density reduces engine power, a higher density increases engine power and exhaust
smoke.
Sulphur: A high amount of sulphur (not normally found in Europe, North America or Australasia) can cause
engine wear. Where only high sulphur fuels are available, it is necessary to use a highly alkaline lubricating oil
in the engine or to renew the lubricating oil more frequently, see table below.
Fuel sulphur
content (%)
Oil change
interval
<0.5 Normal
0.5 to 1.0 75% of normal
>1.0 50% of normal
Distillation: This is an indication of the mixture of different hydrocarbons in the fuel. A high ratio of light-weight
hydrocarbons can affect the combustion characteristics.
Low temperature fuels
Special winter fuels may be available for engine operation at temperatures below 0
O
C. These fuels have a
lower viscosity and also limit the wax formation in the fuel at low temperatures. If wax formation occurs, this
could stop the fuel ow through the lter.
If you need advice on adjustments to an engine setting or to the lubricating oil change periods which may be
necessary because of the standard of the available fuel, consult your nearest Perkins distributor or Wimborne
Marine Power Centre,