Frederico1984
New member
Honda Outboard Engine – No Start / Fuel Pump Not Activating
Hello everyone,
I’m having a problem with a Honda outboard engine that won’t start, and I’d like to present the case in an organized way to get some advice.
Problem description
The engine does not start.
The failure appeared suddenly: the engine was completely dead and did nothing.
The main relay was replaced, after which the engine started cranking, but it still does not start.
Everything seems to work normally except for the fuel pump, which does not activate.
Tests performed
The fuel pump was tested independently, powered directly with voltage, and it works correctly.
The issue appears to be with fuel pump activation, not the pump itself.
A test was done by running a direct wire from the ECU to the fuel pump, bypassing the relay, and in that case the pump activates correctly.
The fuel pump relay is new, and two different new relays were tested with no change.
Engine rotation sensors were checked:
Crankshaft rotation sensor
Position sensor
Both are working correctly.
Electrical connections were cleaned:
Connectors
Grounds
Battery terminals
An additional ground wire was added from battery negative to the ECU.
Safety systems were checked:
Kill switch (man overboard switch)
Neutral safety switch (shift control / Morse control)
Current condition
The engine cranks normally.
The fuel pump only runs when powered directly.
It does not activate through the relay under normal ECU control.
Question
What could prevent the ECU from triggering the fuel pump relay?
Any additional tests or common causes on Honda outboards that I should check?
Thanks in advance for any help.
Hello everyone,
I’m having a problem with a Honda outboard engine that won’t start, and I’d like to present the case in an organized way to get some advice.
Problem descriptionThe engine does not start.
The failure appeared suddenly: the engine was completely dead and did nothing.
The main relay was replaced, after which the engine started cranking, but it still does not start.
Everything seems to work normally except for the fuel pump, which does not activate.
Tests performedThe fuel pump was tested independently, powered directly with voltage, and it works correctly.
The issue appears to be with fuel pump activation, not the pump itself.
A test was done by running a direct wire from the ECU to the fuel pump, bypassing the relay, and in that case the pump activates correctly.
The fuel pump relay is new, and two different new relays were tested with no change.
Engine rotation sensors were checked:
Crankshaft rotation sensor
Position sensor
Both are working correctly.
Electrical connections were cleaned:
Connectors
Grounds
Battery terminals
An additional ground wire was added from battery negative to the ECU.
Safety systems were checked:
Kill switch (man overboard switch)
Neutral safety switch (shift control / Morse control)
Current conditionThe engine cranks normally.
The fuel pump only runs when powered directly.
It does not activate through the relay under normal ECU control.
QuestionWhat could prevent the ECU from triggering the fuel pump relay?
Any additional tests or common causes on Honda outboards that I should check?
Thanks in advance for any help.