Gas sheen on water while idling

[gpmck]

2010 Mercury 40hp EFI engine. Noticed a gas sheen on the water today while idling at low RPM. I could also smell a strong gasoline odour. I checked all the fuel lines and they are all tight. I think it's coming from the exhaust (incomplete combustion). The motor has less than 30 hours on it and is well maintained. Ideas and help appreciated. Thanks Gregg (Ontario, Canada). My boat is a 16 ft Misty Harbor Pontoon boat.

 

[gpmck]

Update to the raw gas discharge into the lake. I found a steady sream of gas running out of the bottom of the motor at the steering pivot rod when engine is idling. I checked the gas lines and they are fine with no evidence of fuel in the bottom pan of the motor. I just can't find the origin..frustrating. Any help greatly appreciated.
Gregg

 

[jimmbo]

Get lots of light and observe the engine running without the cowl on. It has to be leaking somewhere

 

[gpmck]

The boat is out of the water and I found source of the fuel leak. A top hose from the VST (vapour separator tank). I think it could be an overflow tube. I'm hoping it's a similar design to the needle/jet system in a carburetor and debris under the needle is causing the overflow. If I'm right, I'm wondering if your great forum group could give me some direction. A video would be great. Thanks Gregg