2008 Yamaha 115 HP outboard Help !!

I have twin 2008 Yamaha 115 HP four stroke. One of the motors stalls when cold started. It idles rough and then when tried to accelerate in neutral to keep it running it shuts down. Finally after a few tries, the outboard will run kind of rough and starts little by little to normalize apparently after it gets hot. Also there is apparently fuel sheen behind the boat on the water. Once the motor is hot and running for a bit, everything is fine again. What could this be ? THANKS !

Down load codes from engine

Thermostat gone bad and is frozen in the open position? Pull thermostat when cold and see if it is frozen in the open position - should be closed when cold.

Check fuel system, Water/fuel separators,filters,lines kinked, Gummed up fuel system

I missed this... Fuel sheen in the water? Can you tell if it is forming by the engine that is misbehaving? I know it is tough to tell as only a few drops will quickly spread and you won't be able to tell where it came from. While trying to start and starting the misbehaved engine have someone standing back there watching to see if some drops of fuel fall from the base of the engine and hit the water. Pull the cowling and smell for gas fumes... Could have a small cut/worn fuel line or fuel leak inside the engine. Any fuel leak from a hose or fitting inside the engine eventually makes it's way out through the small drain holes around the base. Drip-Drip. It may start running well because the fuel pumps have delivered enough pressure and filled air voids in the fuel system created by the leak or the air has been pushed through and passed created by a slow leak after some idling time.