What the Fuel Stop Solenoid (Perkins / Deutz / Cummins) does
The fuel stop solenoid opens or closes the fuel supply at the injection pump. On an energise-to-run engine it must be powered for the engine to run; on an energise-to-stop engine it is powered to shut the engine down.
Because it decides whether fuel reaches the engine at all, a weak or failed solenoid gives some of the most confusing faults — a perfectly healthy engine that cranks but will not fire, or one that keeps running after the stop command.
Signs it needs replacing
- The engine cranks normally but will not start.
- The engine will not stop from the controller or emergency stop.
- An audible click is missing when the set is started or stopped.
- The solenoid is very hot, or its pull-in coil has burnt.
Get the right part first time
Send us these on WhatsApp and our engineers will confirm the exact part before you pay:
- A clear photo of the old part, including any label, stamping or part number on it.
- A photo of the engine dataplate — the engine serial number decides the exact part.
- Whether your set is 12 V or 24 V, and whether it is energise-to-run or energise-to-stop.
Fitting notes
Check the supply first: many "solenoid faults" are a blown fuse, a failed relay or a loose wire in the panel. When fitting, the plunger travel must be adjusted so it fully opens and fully closes the fuel lever — a solenoid that does not reach full travel overheats and fails again.
Frequently asked questions
How do I test a stop solenoid?+
With the ignition on, check the solenoid has supply voltage and listen for it pulling in. If it has voltage but does not move, the solenoid is faulty.
What is the difference between energise-to-run and energise-to-stop?+
Energise-to-run solenoids need power to keep fuel flowing; energise-to-stop solenoids are powered only to shut the engine down. The replacement must be the same type.
My engine won't stop — what should I do?+
Use the emergency stop or the manual fuel cut-off lever on the injection pump if fitted, then have the solenoid and controller checked before running the set again.