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  1. #1

    Default How do you tell you need need

    How do you tell you need need new risers or manifolds before there is catastrophic failure. The only method that I know is if they are too hot to touch they need replacing.

  2. #2
    Join Date
    Apr 2001

    Default " The best way is to remove th

    " The best way is to remove the risers and inspect the mating surfaces of both the manifold and the riser as this is where 99% of failures occur. You should also look as the cooling passages. After cleaning surfaces, reassemble using a new gasket. If you have an inboard or an I/O with thru transom exhaust, you can watch the water flow. With the engine running, flow should be the same on both sides.
    Good luck. "

  3. #3

    Default Is Merc. Service Bulletin 99-

    Is Merc. Service Bulletin 99-10 still effective? It says to use sealant on exhaust elbow gaskets but I have seen many posts saying not to use sealant.

  4. #4

    Default What is the torque spec for M

    What is the torque spec for Merc 454 FWC exhaust manifold?

  5. #5
    cert merc tec's Avatar
    cert merc tec Guest

    Default " Mercury went back to the dry

    " Mercury went back to the dry joint and old style gaskets, they tried a new gasket and red lock tight 510 alls it made was a mess. Torque spec on risers and manifolds are 33 lb ft. The new full closed cooling for riser blocks and elbows are in the range of 45lb ft. "

  6. #6
    woodenhead's Avatar
    woodenhead Guest

    Default Looking for 2 right risers fo

    Looking for 2 right risers for a 283 engine

  7. #7
    Jerry Hunt's Avatar
    Jerry Hunt Guest


    Great deals and free shipping. I've just "saved" my Crusaders. Risers clogged and cracked. Water in manifolds and scaling in chambers. Pulling heads for an inspect. I'm replacing risers every four years max. Forget hours. I just bought this boat with 150 hours on engines and now this is happening due to previous owners neglect. Boat sat for 3 years with saltwater in risers and who knows where else. Also riggin a freshwater flush for heat exchangers and risers.

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