How to clean a mercruiser flame arrestor

Written by kevin mclain
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The flame arrester on a Mercruiser boat engine is mounted over the top of the carburettor. The purpose of a flame arrester is to extinguish any flames that might result from excessive fuel combustion. The flame arrester will not only extinguish the flame but it will also prevent the flame or fire from spreading to other areas of the carburettor or the engine. Ultimately, the flame arrester will also protect any people who are near the carburettor when the excessive fuel combustion occurs. Cleaning the flame arrester on a consistent basis will keep the arrester working properly.

Skill level:

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Things you need

  • Adjustable wrench
  • Bucket
  • Liquid dish washing soap
  • Clean water
  • Clean rags
  • Compressed air with hose attachment
  • Torque wrench
  • Socket set

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  1. 1

    Gently pull the crankcase ventilation hose off of the flame arrester and the valve cover. Place the hose on a dry surface.

  2. 2

    Loosen and remove the nut and washer from the top of the flame arrester with an adjustable wrench. Place the nut and washer in a safe area. Pull the flame arrester off of the Mercrusier carburettor and place it on a dry surface.

  3. 3

    Wash the entire surface of the flame arrester with clean soapy water. Rinse the soapy water off with clean water. Wipe the flame arrester dry with a clean dry rag.

  4. 4

    Use compressed air to blow out the entire flame arrester to remove any debris and to completely dry the flame arrester.

  5. 5

    Place the flame arrester back over the top of the carburettor. Place the washer over the stud and screw the nut on tightly. Finish tightening the nut with the adjustable wrench. Torque the nut to 106 inch pounds with a torque wrench and a socket.

  6. 6

    Reinstall the crankcase ventilation hose back onto the flame arrester and the valve cover.

Tips and warnings

  • You can also use a solvent such as brake cleaner or parts cleaner to thoroughly clean the flame arrester. If using a solvent, be sure to completely dry and remove the solvent with the compressed air.
  • Do not smoke or use open flames when cleaning a flame arrester.

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