Advertisement
Ash (by weight) (max). ............
Sulphur (by weight) (max)........
Class A1 fuel is intended primarily for automotive use.
Class A2 is a general purposes fuel.
(i) Winter and summer grades of diesel fuels are marketed during the
appropriate seasons and are also graded for that part of the world in
which they are intended to be used Diesel fuels available for use in low
temperature climates are classified as 'Cold Start Reference Fuels'
Make sure that the fuel being used is suitable for the prevailing
temperature conditions
(j) Fuels for marine auxiliary engines required to operate under constantly
differing climatic conditions should be suitable for the coldest
conditions likely to be encountered This is particularly important when
considering fire pumps, etc., required to operate in an emergency
Some diesel fuels not suitable for low temperatures may form wax
(k)
under these conditions. If it is suspected that wax has formed, the
whole engine should be gently warmed throughout and the fuel tank.
pipes, injector and fuel injection pump then completely drained and
flushed with the correct fuel. Refill the fuel system with correct fuel and
bleed and prime before attempting to start.
8. Governing
The governor controls the engine at a constant speed irrespective of load
variations and will be either a fixed speed type governing the engine at its
rated speed only or a variable speed type allowing the governed speed to be
varied between idling and full rated speed
The centrifugal forces on the governor balls are transmitted to the fuel
pump rack These forces, which vary with the speed of the engine, are
balanced by an adjustable speeder spring On a variable speed governor the
tension of the speeder spring may be externally altered to give the required
governed speed On fixed speed governors the Speeder spring may be
adjusted to give an included variation of 10%
For starting purposes only. operation of the overload stop lever fitted to
variable speed governors allows the fuel pump rack to move into the excess
fuel pump position When the engine runs up to its rated speed the governor
closes the rack which is then prevented from returning to the excess fuel
position by the ratchet action of the overload stop cam
The overload stop limiting the travel of the rack into the excess fuel
position on variable speed engines is set by Petters Ltd and the internal
adjustment should not be disturbed. Interference with the setting may result in
the engine being overloaded or not delivering its rated power Excessive load
must be avoided and this will be indicated by the engine running below its
RATED speed and/or a dirty exhaust.
0.01%
0.5%
16
0.01%
1.0%
Advertisement
