Well it sounds like you're right to suspect the fuel cut-off valve wether it's mechanical or a solenoid. I've never had that problem so I can't help you with taking it apart.
My Perkins are all in Hysters so I don't know if the Linde version is exactly the same. All my Hysters have solenoid stop valves.
If you put your email in your profile I'll see if I have any info on it.
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