Mercury 75HP EFI engine fuel leaks

[dougd1]

My Mercury 75 HP EFI engine simply stopped on the weekend. We had just launched and left the dock. About 5 minutes later, I put the motor in neutral and then it stopped. Tried to restart, but it would not fire. Eventually i It would not turn over, but ended up leaking a large amount of fuel - wasn't sure where it was coming from. Tried it again today - very similar - it would not turn over, but had a large amount of fuel coming out of the air inlet manifold. Any ideas as to what the issue may be? Thanks.
Doug

 

[crazyinkc]

Do you have an engine serial number? That would help us know what version of the EFI you have as far as the FSM, ECM, etc. Fuel coming out of the manifold sounds like a stuck injector. I'm no expert on the Mercury EFI but I have had issues with automotive EFI where an injector will get stuck open and fill the cylinder with fuel. Pull the injector connectors and measure for voltage with the key on and see if any of them are getting voltage without a crank signal. That could be a bad ECM. Again, not an expert just going off automotive issues from the past.

 

[crazyinkc]

Disconnect the FSM before you do the voltage test. If it's a mechanically stuck injector, the engine will fill with fuel with the connectors off.

 

[dougd1]

The engine serial number is 1B70xxx. If it is a bad injector, would one bad one prevent all the others from working? I would have thought the other three would at least fire when the engine is turned over when starting.
I came across a youtube video where the it was a different symptom, but in his description of the fuel system and how it operated, it matched what was happening on my engine. His description indicated a failure of a hose on the fuel pressure regulator inside the fuel system module (where the low and high pressure pumps are situated) would cause fuel to go into the fuel vent canister, which, when purged, dumps fuel into the intake inlet. Didn't quite understand it because it sounded like it required two concurrent failures - the fuel regulator hose and the vent canister float switch. But the symptom sure matched what I saw on the engine.