1987 mercury classic 50 stalling at 2500 then goes to 5000 after removing fuel line

[gregory1943]

I have a 1987 mercury classic 50 when accelerating from idle to full throttle the engine goes to about 2500 rpms then stalls if i remove the fuel line it will go to 5000 almost instantly if i replace the fuel line it boggs down i can repeat the several times and it does the same thing every time. HELP

 

[racerone]

You have an issue with fuel pump diaphragm.---------Or an issue with carburetor float valves / adjustment of floats.---------Easy fix I would say.

 

[GA_Boater]

What Racer said and it could be the tank vent ( open the filler cap) if the tank is built in or an air leak in the fuel line between the tank and motor fuel connection. As he said, should be an easy fix.

 

[QBhoy]

Sounds very like the fuel tank vent is closed. Let us know how you get on.