Mercury 9.9 HP fuel problem

[Buckeyeshane]

I have a problem with a 9.9hp Mercury 2 stroke outboard motor. I am not sure of the year of the motor (the serial # on the motor is 08101084). The problem is the fuel line going directly into the motor (after the primer bulb) goes into what looks like a fuel filter (not sure) and it fills up with fuel and overflows out of it like it's not sealed. When the motor is idling it will drain this fuel filter or whatever it is then start to starve for fuel until i pump the primer bulb to fill it back up. What is this part?? Being that when I fill it with the primer bulb and the fuel flows out the top of it is it my problem?? When we are out on the lake running WOT it runs fine until this runs out of fuel in this part then I just pump the primer a few times and were good for another few minutes. Thanks for any responses

 

[flydown]

Re: Mercury 9.9 HP fuel problem

I am certainly no expert. In fact, I probably know less than you about outboards but I have been doing research for my own problems with the same motor. It sounds as though you are referring to the fuel pump. I probably has a torn diaphram and that is keeping from pulling a vacum and pumping fuel. When you pump the primer bulb, you are filling the bowl on the bottom of the carb and when it runs out of fuel, your motor will die.
If any of the experts on here disagree, please give him the correct info.
Hope this helps

 

[Buckeyeshane]

Re: Mercury 9.9 HP fuel problem

Thanks, but I thought the fuel pump on there were inside the carb?? This is on the outside of the carb and the fuel line coming in plugs directly into it?

 

[flydown]

Re: Mercury 9.9 HP fuel problem

Yes that is the fuel pump. When you pump the bulb, you are forcing fuel past the pump and into the bowl on the carb. When the motor burns the fuel that is in the bowl, it is then starved for fuel because the pump is not keeping the flow going. Remove the center screw and this will detach the fuel line from the pump. Then remove the four screws that attach the pump to the side of the carb. Under there you will find a diaphram. Most likely it has a tear in it. That would keep the pump from being able to pull the vaccum nessesary to pump fuel. Replace that diaphram and that should solve the problem.
Hope this helps.

http://forums.iboats.com/showthread.php?t=314943

Read the reply left by green4themoney.

 

[Buckeyeshane]

Re: Mercury 9.9 HP fuel problem

Thanks for the reply, I ended replacing the fuel filter with an inline fuel filter and everything works normally now. The fuel filter I replaced did not have a gasket/o-ring when I took It apart so I could have fixed it for about $0.50 but I had already installed the inline filter.