Engines of the same series are frequently serviced with more
than one fuel pump type. Visible differences between the pump may be the cover
inlet or outlet or the separator ring position.
The cover position or separator ring position are determined
The angle between the rocker arm and the fuel inlet is expressed in terms of
clock position. Place pump with rocker arm in the 12 o’clock position. Observe
the relationship of the fuel inlet to the rocker arm. This position is the clock
position of the pump. Examples of this in the outline drawing shows that if the
fuel inlet is at position "A", it is considered a 6 o’clock pump, if
at position "B", a 3 o’clock pump, and at position "C", an
8 o’clock pump.