Problem

The engine runs poorly.                                                

This may be due to the stop valve on the diesel pump not opening properly. Change to a new stop valve.

Or: Air leakage somewhere between the tank and the pump. Clogged diesel filter. Water in the diesel filter. Error on the maximum quantity regulator. Clogged nozzles.

Problem

The engine sputters or cuts out.

This may be because the line on the stop valve is almost broken off, or screwed on too poorly.

If the cap has cracked, it will not hold the cable stably in place, and vibrations can thus cause it to break or come loose.

Hood with a crack. Put on insulating tape or shrink tube.

Problem

The engine will not stop, even if the ignition is turned off.

This may be due to the stop valve not closing properly for the diesel supply. (Or that it still gets power, but that is unlikely.)

Switch off the motor with the mechanical stop lever on the pump.
Reolace the stop valve.