How to Remove the Cylinder on a Jet Ski

Working on a Jet Ski engine requires some mechanical know-how. Fortunately, Jet Ski engines are small. So you can repair one in the comfort of your garage, particularly if you need to replace the cylinder chamber. The process involves straightforward steps, but they must be implemented correctly. Otherwise, a part won't fit or will be installed incorrectly. However, once you replace your first cylinder, future engine work will seem fairly straightforward, rather than a challenge.

Things You'll Need

  • Socket wrench and sockets
  • Rubber mallet
  • Shop rag
  • Circlip tool
  • Piston gudgeon pin tool
  • Cylinder gaskets
  • New piston bearing
  • New piston and rings
  • New cylinder
  • New spark plug
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Instructions

    • 1

      Lift the Jet Ski engine cover. Access the engine and locate the cylinder -- which typically has a spark plug connected to it. Pull the ignition cap wire off the spark plug. Insert a socket wrench and remove the existing spark plug. Use a longer socket to loosen and remove the cylinder cap securing nuts. Remove the nuts and washers off the cylinder cap.

    • 2

      Pull the cylinder cap off the engine cylinder. Grab the cylinder with both hands, and pull the unit off the engine carefully. Use a rubber mallet to give it a budge, if stuck. Keep pulling the unit until the pistons have almost slid out the back. Place a shop rag under the piston -- or both pistons, if applicable -- to catch them. Free the old cylinder and place it aside.

    • 3

      Use a circlip tool to remove the securing circlips from the side of the piston -- or both pistons, if working on a four-stroke engine. Insert the gudgeon pin tool, and secure it on the other side of the piston. Twist the tool handle to remove the gudgeon pin inside the piston. Pull the piston off the crankshaft arm, and remove the old piston bearing. Repeat the step for each existing piston.

    • 4

      Insert a new piston bearing in the end of the crankshaft arm. Place a new piston with piston rings over the arm and bearing, inserting the gudgeon pin to connect all the parts. Push the pin into the piston with your thumb to keep it in place. Finish the insert by again pulling the pin in place with the gudgeon pin tool. Reinsert the circlips with the circlip tool to finish the piston attachment. Repeat the step for each piston as it applies.

    • 5

      Place a new engine cylinder gasket on the surface of the engine case where the cylinder meets with it. Grease the insides of the new cylinder with engine oil normally used in your Jet Ski. Carefully place the cylinder back onto the engine studs extending from the case. Slowly slide the cylinder back onto the engine, squeezing the new pistons and rings back into the cylinder. Push the cylinder home, and tap it down with a rubber mallet to seat it onto the engine case.

    • 6

      Reinstall the cylinder cap after applying a cylinder gap gasket, if required. Place new nuts and washers on the cylinder studs, and tighten the cap again with a socket wrench and sockets. Reinsert the spark plug, and tighten it as well with the socket wrench. Reattach the ignition cap and wire to the spark plug. Close the engine lid, and test the engine by running it.