How to Mount a Fuel Pump on a 1974 9.9 hp OMC

When you need to install a fuel pump on the 1974 OMC outboard, the procedure is exactly the same as working on the same model year Johnson or Evinrude outboard. The difference is that the OMC pump presents a diamond-shaped face, whereas the Johnson and Evinrude pumps were square. With a few hand tools, a new pump and some general marine supplies, you can make the changeover from an old pump to a new.

Things You'll Need

  • Shop rag
  • Razor knife
  • Wire cutters
  • Duct tape
  • 3/16-inch socket
  • Medium thread locker
  • Marine grease
  • Inch-pound torque wrench
  • Plastic fuel line ties
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Instructions

  1. Removal

    • 1

      Work the latch on the back of the engine and lift the engine cover completely off. Remove the fuel tank's filler cap and set the fuel tank beside the engine.

    • 2

      Place a shop rag underneath the joint between the fuel pump and the fuel line on the side of the pump that leads to the carburetor. Cut the plastic tie that holds the line to the pump with a razor knife or a pair of wire cutters without nipping the hose.

    • 3

      Tag the fuel lines to indicate which was attached to the fitting on the front -- the pump inlet -- or to the discharge fitting on the side of the pump by wrapping a piece of duct tape around the pump inlet fuel line.

    • 4

      Push the fuel lines off the nipples on the pump. Hold the pump inlet fuel line upright and move it over the open fuel tank. Drain any excess fuel in the line into the tank.

    • 5

      Remove the two hex-head bolts on either side of the face of the diamond-shaped fuel pump using a 3/16-inch socket. Do not remove the bolts at the top and bottom of the face of the pump; they hold the housing cover and body assembly together.

    Installation

    • 6

      Scrape any remaining gasket material from the mating surface on the powerhead before you install the new pump.

    • 7

      Coat the threads of the pump retaining screws with a medium thread locker. Apply marine grease to the new pump's O-ring.

    • 8

      Position the O-ring around the base of the pump. Position the pump onto the powerhead. Thread the pump retaining screws through the mounting holes on the left and right sides of the pump body and into the bores on the powerhead. Tighten the bolts as snugly as possible with your fingers, then tighten to 32 inch-pounds with an inch-pound torque wrench.

    • 9

      Push the fuel line onto the pump nipple. Secure the line in place with new plastic ties.

    • 10

      Cap the fuel tank. Squeeze the fuel primer bulb to charge the fuel system. Visually inspect the fuel line, the junction between the fuel tank and the fuel line and the junction between the fuel line and the fuel pump for any leaks.

    • 11

      Replace the engine cover.