How to Separate Rusted Exhaust Components

A rusted boat exhaust system is a potential engine-killer. It allows water a way into the engine's combustion chambers. It's a slow death that begins with a death rattle -- a clanking from rusted exhaust risers being shaken by both the exhaust hose on one end and the exhaust manifold on the other. A cracked manifold, admitting noxious vapors into the boat's interior, is often rusted to the engine block. The problems end when the engine's block cracks and leaves you stranded, when the noxious vapors overcome you and your passengers and you die or when you separate the rusted components, remove them and replace them.

Things You'll Need

  • Moisture-excluding, penetrating lubricant spray
  • Phillips screwdriver
  • Appropriately sized socket set
  • Ratchet
  • Rubber gloves
  • Naval jelly
  • Disposable paintbrush
  • 5 tablespoons bicarbonate of soda
  • 5-gallon plastic bucket
  • Water hose
  • Razor knife
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Instructions

    • 1

      Spray a copious amount of moisture-excluding, penetrating lubricant on the bolts securing the riser to the exhaust manifold -- there are usually three, four, or six, depending on the make and model of the engine.

    • 2

      Spray the penetrating oil on the bolts holding the exhaust manifold to the engine block or, in the case of an outboard, the powerhead. Spray the same penetrating lubricant on the screws securing the hose clamps that hold the exhaust hose to the riser and the exhaust outlet. Wait 30 minutes.

    • 3

      Attempt to loosen the hose clamps that hold the exhaust hose to the riser and the exhaust outlet using a Phillips screwdriver. Push the hose off the end of the riser. If the hose clamps on the riser won't budge, attempt push the hose off the exhaust outlet's fitting. Take notice of any hose-clamp screws that don't turn.

    • 4

      Loosen and remove the bolts holding riser and manifold together using an appropriately sized socket and a ratchet. Take note of any bolts that appear irreconcilably stuck.

    • 5

      Don rubber gloves, as naval jelly is based on a corrosive, phosphoric acid. Apply naval jelly to any bolt or hose-clamp screw that refuses to budge, using a disposable paintbrush and without getting any of the compound on the exhaust hose itself. Wait 10 minutes.

    • 6

      Dust 5 tablespoons of bicarbonate of soda on the bottom of a 5-gallon plastic bucket.

    • 7

      Place the bucket under the first bolt from which you will remove the naval jelly. Rinse the naval jelly from the bolt or screw using a water hose so that the water and the naval jelly flow into the bucket.

    • 8

      Remove the screws or bolts, using the appropriate socket or screwdriver, and remove the manifold, riser or exhaust hose.