Help for an Exhaust Leak Under the Hood of My 1993 Evinrude 30 HP

Exhaust leaks under the hood of most Evinrude outboards result from a warped, leaking exhaust cover, usually the result of overheating. But the 1993 Evinrude 30-horsepower outboard lacks an exhaust cover. Instead, the exhaust housing is at the lower end of the powerhead, the outboard's engine block. While the gasket between the powerhead and the exhaust housing is the likely culprit, you must remove the powerhead to access the gasket. While you're there, you can check for more serious damage that requires professional help.

Things You'll Need

  • Screwdriver
  • 1/4-inch socket
  • 9/16-inch socket
  • Engine hoist
  • Pry bar
  • Clean cloth
  • Acetone
  • Wide-blade putty knife
  • Dowel pins
  • Gasket sealing compound
  • Powerhead-to-exhaust-housing gasket
  • Torque wrench
  • Torque driver
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Instructions

  1. Removing the Powerhead

    • 1

      Trigger the latch on the back of the engine top cover. Remove the top cover,

    • 2

      Loosen the retainer knob at the center of the air silencer housing. Lift the silencer and disconnect the hose from its bottom. Remove the silencer from the engine. Disconnect the choke cable pin from the retainer and remove the cable from the bracket on the powerhead. Remove the six screws holding the lower cover in place, using a screwdriver. Remove the wire tie holding the fuel hose to the quick-connect connector and disconnect the fuel hose. Remove the lower engine cover.

    • 3

      Remove the cable ball socket from the ball on the throttle lever. Separate the shift rod from the shift lever. Remove the two screws holding the cable trunnion anchor block to the powerhead. Remove the two bolts holding the tiller arm, using a 1/4-inch socket. Pull the tiller arm from the engine. Remove the steering lever.

    • 4

      Unplug the two-pin connector for the low oil light. Remove the three recoil starter mounting bolts, using a 9/16-inch socket. Lift the recoil starter from the powerhead. Replace the recoil starter with the lifting eye. Thread the recoil starter bolts into place just enough to hold the lifting eye in place.

    • 5

      Remove the seven bolts bolts threaded upward from the exhaust housing upper flange into the powerhead using a 9/16-inch socket. Attach an engine hoist to the lifting eye. Lift the powerhead slowly. You may have to use a pry bar to help separate the exhaust housing from the powerhead. .

    Inspection and Minor Repair

    • 6

      Inspect the mating surface on the powerhead visually. The surface must be clean, free of dirt, sealant or gasket materials. Clean the surface with a clean cloth soaked in acetone and a wide-blade putty knife to scrape any gasket material or sealant away gently to avoid scratching the surface. Repeat the visual inspection for the exhaust housing's mating surface.

    • 7

      Drag the edge of a fingernail across the mating surfaces. Scratches deep enough to snag a nail dragged across the surface can cause an exhaust leak. Inspect the mating surface for cracks or other damage.

    • 8

      Ensure that the mounting dowel pins that index the mating surfaces are in place and not loose or damaged. Replace them as necessary.

    Reinstall the Powerhead

    • 9

      Apply gasket sealing compound to both sides of a powerhead-to-exhaust-housing gasket. Apply the gasket sealing compound to the threads of the seven exhaust housing bolts. Position the gasket on the exhaust housing.

    • 10

      Lower the powerhead onto the exhaust housing. Install the exhaust bolts through the exhaust housing up into the powerhead. Tighten the bolts to 200 inch-pounds with a torque wrench.

    • 11

      Connect the shift arm to the shift lever using the screw you removed. Tighten the screw to 100 inch-pounds with a torque driver.

    • 12

      Replace the lifting eye with the recoil starter. Apply thread locker to the three retaining bolts and tighten to 74 inch-pounds with a torque wrench. Engage the oil light’s two-pin connector and secure the connector to the ignition module.

    • 13

      Replace the lower engine covers. Reinstall the tiller arm. Replace the trunnion anchors. Reconnect the throttle cable ball socket to the throttle lever. Connect the shift cable to the shift lever. Secure the cable on the side of the powerhead with its clip.

    • 14

      Reconnect the fuel line, all electrical cables and grounds. Connect the drain hose to the bottom of the air silencer. Return the silencer to its place and secure with the silencer's lock knob.

    • 15

      Replace the engine's top cover.