Merc 15HP Carb Flooding

[Oldsmotion]

I have a 1999, Mercury 15hp 4 stroke. It'll start fine, but within 5 seconds gas is flowing out of the carb at every possible location and the engine soon quits.

I took the carb apart. Clean as new. No dirt, no gum, nothing. Float looks ok. No sign of cracks and floats in gas.

Time for a carb rebuild? Could the fuel pump be the problem? Is there a way to check the pump pressure?

The engine looks exactly like my neighbors Yamaha 9.9hp. I read somewhere Yamaha made the power heads while Mercury made the lower unit. Not sure if this is true but should I be shopping Mercury parts or Yamaha?

Thanks

 

[BOAT DOCTOR]

Re: Merc 15HP Carb Flooding

take your fuel pump off leave the fuel lines hooked up and prime the bulb and see if fuel is leaking out of hole behind the fuel pump if so could be a busted diaphram

 

[Oldsmotion]

Re: Merc 15HP Carb Flooding

Took fuel pump off. No fuel coming out from the back side while pumping the primer bulb. All fuel coming out of the exit port of the pump.

Thoughts? Carb off and rebuild with new gaskets, needle and seat and maybe float?

 

[DADDYRABBIT1]

Re: Merc 15HP Carb Flooding

Yes, for it to leaking in as many places as you are saying I would rebulid and take that out of the equation.