[daguvna]

I have a 1999 200hp EFI Saltwater series Mercury outboard. The electric fuel pump starts running when the ignition key is first turned on but will not quit when, I assume, the correct fuel pressure is attained. The motor will start but will try to flood out. Is the pump controlled by fuel pressure? If so, is there a sensing switch? Is this replaceable or is it contained in the fuel pump assembly?

Thanks for your help in advance.

[WillyBWright]

The electric fuel pump runs when the motor runs. It doesn't shut off unless the motor isn't running. It should stay on with the key for up to 20 sec and stop, but resume with cranking. If you're flooding, it's a bad diaphragm on one of the regulators (rare) or you have a sticky injector. Or possibly a torn diaphragm in the diaphragm fuel pump, but that would only flood one or two cylinders.

[glen357]

Is this an injector pump you hear or a fuel pump?
I have a '93 200hp efi and my fuel pump is a vacuum pump. I do hear the injector pump build up when I turn on the key. G

[daguvna]

Originally Posted by glen357

Is this an injector pump you hear or a fuel pump?
I have a '93 200hp efi and my fuel pump is a vacuum pump. I do hear the injector pump build up when I turn on the key. G

[daguvna]

I believe you are correct in that it is the injector pump or, as Mercury calls it, the fuel management system. I am not siure if the problem lies in the fuiel pressure regulator or a bad injector. I am still researching the cause.