Force mercury 150 pouring gas

[jdsbbq1]

I am new here,but I have just recently bought a 1992 force mercury 150 3 carb 5 cyl outboard that sat for about 2 years and fired right up and ran on first try on test ears in my driveway but when I took it to lake and started it, top carb started pouring out fuel and flooded out,so I bought 3 new valve needles and gasket sets and cleaned and replaced all but floats in all 3 carbs.Note-the seats are pressed in so I just cleaned them,and set the floats level.Reinstalled the carbs and it started right up but after 10 seconds of idling the top carb starts pouring gas out the throat and overflow! So I changed the top carb only with a known good one and same thing again! I disconnected the fuel primer AKA choke system and still flooding out the top carb ONLY! What am I doing wrong???????

 

[pnwboat]

Only thing that would cause that is the needle valve is not sealing. Could be a fuel logged float (if it's the black styrofoam type float) , debris caught between the needle valve and seat, float adjusted too high. Installing an in-line fuel filter between the fuel pumps and the carburetors will help keep junk out of the carbs. Sometimes pieces of the fuel pump diaphragm or fuel hose flake off and get caught under the needle valve.

 

[jerryjerry05]

Float level not set right.
Or debris in the bowl.
The fuel primer shouldn't have nothing to do with 1 carb flooding.
There is a diaphragm in the enricher that can go bad and affect the performance by feeding too much gas into the system while running.