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  1. #1
    skiversinc's Avatar
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    Sep 2007
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    Falmouth, Cornwall, UK
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    Cracked exhaust manifold

    Any idea what would cause an exhaust manifold to crack?
    I finally got the ski back on the water yesterday, after nearly a year off the water.
    Tested it on the hose, running great. Got it on the water, running great for most of the day. Then, later on when I went out again from the beach, I was only getting 5000 rpm instead of the usual 7000! She was also getting quite unstable & twitchy.
    Got her into a nearby beach & found that the hull was almost full with water. Started her up in neutral to operate the bilge pump (without draining the battery) and found that there was water **ssing out of the side of the exhaust manifold, near, but not on, the joint of the main pipe.

    I've split the offending object off now & have found that the whole top section is nearly falling off with a 5" split down one side of the pipe and a crack virtually all the way round where the pipe bolts on!
    Any ideas as to what would cause this issue?
    I now need another exhaust manifold & gaskets to get her back on the water, but don't want the same thing to happen again.
    I will take some photos to try to show the split.


  2. #2
    skiversinc's Avatar
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    Here's some photos to show the damage.
    Click image for larger version. 

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  3. #3

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Freeze damage?

    Incorrect bolt torque?

    Incorrect or missing spacer/washers on the lower mounting points?
    (Going from memory on this last one. I forget which engines have some flat spacers between the manifold bosses and the engine case)

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