A diesel that keeps running with the key off is a failed fuel cutoff — and it won't fix itself. Don't run the boat until it's repaired.
What to Check
1
Fuel solenoid (electric stop)
Most modern diesels use a 12V solenoid on the injection pump. When it fails, the engine won't stop.
2
Manual stop cable
On older diesels, a Morse cable physically pulls the stop lever. Cable corrosion = engine won't stop.
3
Air cutoff
Last-resort emergency stop is to cut combustion air. Locate yours before you need it.
4
Fuel-rack stuck
Internal injection pump issue — needs a diesel specialist.
When to Call Us
Same day. We carry common Yanmar, Volvo, Westerbeke, and Cummins fuel solenoids and stop cables.