How do I change the fuel filter on my 1977 mercury 70ho outboard motor?

The motor starts fine but when I throttle up it bogges down. After a few minutes it takes off at full throttle.

2 Answers

  • 7 years ago
    Favorite Answer

    I agree in part with SBO in TX , There are 2 fuel filters on that motor. One is inline just before the fuel pump, and a .secondi inside the fuel pump.


    I think your problem is a bit more than filters, which should be changed anyway. I think you need to clean your carburetors, or have that done by a mercury shop.

  • The fuel filter is an inline see through cylinder inside the motor cover. You can follow the fuel line from the primer bulb right to the filter -- might go through the fuel pump on the way. I think you're bogging down under heavy load because the cold engine hasn't enough power to do as you ask it to do. I respectfully suggest you buy an Attwood (or other) fuel/water separator ($29 at WalMart) and install near the fuel tank. It's a spin off, and can be changed annually. Alcohol in the fuel evaporates fairly quickly, chilling the air in the tank, which causes condensation. Most new boats have a fuel/water separator, but older ones (like yours and mine) didn't come with them.

    Source(s): boater
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