Re: [MV] Cummins run away

From: noel shelley (noel@shelley1722.freeserve.co.uk)
Date: Sat Jun 11 2005 - 09:06:38 PDT


Hi Joe ,
             Has your engine got an conventional injection pump ?ie in-line
or rotary ? Is it air governed , hydraulic or mechanical ?
OR is it Cummins P/T {pressure/time injection system}
This last method involves cam operated pump/injectors in the head , fed from
a main pump !
Hydraulic governing involves the fuel pressure and somewhat perversely ,if
the fuel filters are partially block the drop in pressure is seen as a
command for more fuel and off she goes !
Mechanical governing is a simple centrifugal arrangement of rotating weights
and springs , BUT if there is corrosion due to water in the fuel or the
fuels lubricity is too low things can
stick , sometimes, open othertimes shut !
Once started a diesel engine can ONLY be stopped by cutting off the fuel ,
stopping the combustion air , or by over powering the rotating force ! THERE
IS NO IGNITION SYSTEM !
BUT first you need to know if she`s running away on diesel fuel or some
other ? Engine or diesel oil finding it`s way into the combustion chamber
in an uncontrolled manner will result in a runaway and potentially
catastrophic failure of the engine , read explosion , in spectacular form !
The normally accepted method is to stop the incoming air BY ANY method ,
lump of wood , sheet of steel , BUT NEVER ANY PART OF YOUR BODY { a runaway
beats any vacuum cleaner }
If water finds its way into rotary pumps ,the first sign of trouble in road
vehicles is that the engine will often stop when called upon to tickover !
It will restart fine ! This is a sign that the fuel valve in the pump is
sticking , and will soon stick for good ,leaving you stranded !
There is nothing you can do except have the pump rebuilt at a considerable
cost ! ie $500 . Some fuel filters are as little as $3 and draining the
filter bowl is easy ! A SOUND INVESTMENT !

Hope the above is of interest to some , Noel



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