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Exhaust system configuration

Discussion in 'Chris Craft Roamer Yacht' started by irwindustro, Jan 29, 2012.

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  1. irwindustro

    irwindustro New Member

    Joined:
    Jan 29, 2012
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    7
    Location:
    knoxville, tn
    I own a beautiful 1964 Chris Craft Roamer 36 "aluminum" and I love this boat. I recently blew my starbord engine "Crusader 5.7 carb" due to steam entering the engine. This engine only had 245 hrs, so sad. I just completed the installation of a new engine and do not want to experience the same problem again. The installation book shows the exhaust from the manifold riser to the exhaust port in the hull as having a constatnt drop but both exhausts on this boat have a sag of about 6 inches down to the inline muffler and up to the hull exhause port. Should I change this sag configuration to a constant drop (1 inch per foot) or leave it like it is? Is this a contributor to my steam issue?

    To sag or not to sag??

    Help please! Dusty Irwin
  2. Jim Reed

    Jim Reed Member

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    Sep 25, 2006
    Messages:
    105
    Location:
    Knoxville, Tennessee
    Hey Dusty, Didn't know you were having problems. When you installed the orginal engine, did you replace the exhaust manifolds and risers with new ones? These things go bad after a while and just to be on the safe side I would replace them on your new engine. As far as the drop or sag, this is to keep water from entering the engine thru the exhaust. The sag wouldn't really concern me. I bet you have a bad exhaust maniford (water jacket).
  3. irwindustro

    irwindustro New Member

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    Jan 29, 2012
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    7
    Location:
    knoxville, tn
    Thanks Jim, I wouldn't sacrifice a new motor for the cost of two manifolds. Ordered today. Thanks!!! Dusty
  4. Jim Reed

    Jim Reed Member

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    Sep 25, 2006
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    105
    Location:
    Knoxville, Tennessee
    My cousin is the best boat mechanic I know. In fact, Sea Ray uses him to trouble shoot problems that their people can't figure out. I was at his shop today and told him of your problem. He said you might want to rebuild your carb as well. A carb that runs lean can cause the engine to run hot. Call me if I can help. You've got a great boat.
  5. RT46

    RT46 Senior Member

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    Feb 22, 2011
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    1,018
    Location:
    Long Island, NY
    Risers are usually the weak point,
    Risers should be replaced on the crusader setup every 2-3 years....
    Salt water sits in them and rots them from the inside.
    They can go sometimes without warning, sometimes a little steam is noticible in exhaust, sometimes not, usually a hot engine will suck the sw in through the failed riser.....then it's usually over......
    Consider riser replacement in your maintenance costs....

    Manifolds can last the life of the engine if fw coolod
  6. NYCAP123

    NYCAP123 Senior Member

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    That sag will help prevent back flow. I would not change it. Salt water is not a big concern in Tenn., but the risers would still be my suspect.
  7. irwindustro

    irwindustro New Member

    Joined:
    Jan 29, 2012
    Messages:
    7
    Location:
    knoxville, tn
    I really appreciate the feedback on this issue. I ordered two new risers yesterday. Since these were the only used parts on the new build my concience is eased.
    Thank You! Dusty