How to Rebuild a Fuel Pump for an 85 HP Evinrude

The fuel pump on the 85-horsepower Evinrude is a diaphragm-displacement type of pump, driven by the crankcase as it alternates between a pressurized environment and a vacuum. When you have to rebuild the pump, take every advantage you can, including the use of Evinrude's pump replacement kit and things as simple as a chalk matchmark to make the project move as smoothly as possible.

Things You'll Need

  • Tape
  • Marking pen
  • Screwdriver
  • Chalk
  • Evinrude fuel pump seal replacement kit
  • Thread locker
  • Shop towels
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Instructions

  1. Removal and Overhaul

    • 1

      Push the fuel hoses from the intake and supply nipples of the pump. Tag each hose with tape and a marking pen, and tag the nipple from which you remove each hose to facilitate reassembly. Remove the four screws -- three at the top and one at the bottom -- that hold the pump to the powerhead, using a screwdriver.

    • 2

      Draw a line across the fuel pump's cover and onto the pump housing and base, using chalk, to act as a matchmark when you reassemble the pump. Remove the retaining screw from the center of the cover.

    • 3

      Lift the fuel inlet cover and the diaphragm from the pump body. Note the position of the O-ring from the back of the diaphragm.

    • 4

      Clean the metal parts in a shallow pan of acetone. Scrape away any gasket material remaining on the mating surface of any metal part with a plastic scraper.

    • 5

      Inspect the pump body and all mating surfaces for visible nicks, gouges or irregularities. Lay the edge of a machinists' ruler flat on the face and "shave" the surface to ensure that it's flat, rather than warped.

    Reassembly

    • 6

      Center the new O-ring from the fuel pump overhaul kit over the fuel opening on the face of the pump body. Set the new seal from the overhaul kit centered on the opening.

    • 7

      Set the fuel pump cover in place. Thread the retaining screw through the pump cover and into the pump face.

    • 8

      Align the matchmarks you made during disassembly. Adjust the seal so that it is centered beneath the pump cover.

    • 9

      Tighten the retaining screw. Apply a bead of thread locker to the threads of the four fuel pump screws.

    • 10

      Position the fuel pump on the powerhead, Thread the four fuel pump screws through the pump body and into their bores. Tighten the screws snugly. Push each hose back onto the appropriate nipple.