Troubleshooting Chart - Mercury 40 Service Manual

Troubleshooting Chart

Problem: Warning Horn Stays On When Ignition Key is Turned to "ON" Position (Engine Cold).
Possible Cause
Faulty Engine overheat sensor.
Problem: Warning Horn Sounds (Continuous Beep) When Engine is Running and Oil Tank is Full.
Possible Cause
Defective low oil sensor (located in bottom of oil tank).
90-852572R1 JANUARY 1998
Corrective Action
If warning horn sounds a continuous "beep", the engine
overheat sensor may be faulty. Disconnect tan/blue over-
heat sensor lead at bullet connection. Turn ignition key to
"ON" position. If horn stops sounding, the engine overheat
sensor is faulty.
Corrective Action
Disconnect both low oil sensor leads (blue) at bullet con-
nections. Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty.
FUEL SYSTEM - 3C-9