How to Install Outboard Motor Head Gaskets

Exhaust smoke leaking from your outboard's top cowling is never a good sign. It usually means that you need to install a new head gasket on your outboard motor to prevent exhaust gases from escaping from between the cylinder block and the powerhead block. The procedure is straightforward and, as long as the gasket is sealed and the cylinder block is properly tightened to the correct torque, it should alleviate the problem.

Things You'll Need

  • Adjustable wrench
  • Plastic scraper
  • Gasket sealing compound
  • Clean engine oil
  • Torque wrench
Show More

Instructions

    • 1

      Remove the cylinder block bolts with an adjustable wrench. Lift the cylinder block from the powerhead. Remove any gasket sealing compound residue from the surface of the mating surfaces of the cylinder block and powerhead block, using a plastic scraper.

    • 2

      Spread a thin layer of gasket sealing compound on the top and bottom sides of the new cylinder block gasket and position the gasket on the cylinder block, using the alignment pins on the cylinder block to position the gasket.

    • 3

      Apply a very light coat of clean engine oil to the threads of the cylinder block bolts. Use the alignment pins on the cylinder block to position the cylinder block on the powerhead block.

    • 4

      Thread the cylinder block bolts into their bores and tighten them with your fingers. Tighten the upper bolt on the port side of the block to 9 foot-pounds. Use a crossing pattern to tighten all of the cylinder block bolts to 9-foot pounds, ending at the upper, starboard bolt. Continue to tighten the cylinder block bolts until the torque for all bolts is 19 foot-pounds.