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  1. #1

    Default repowering a 120hp mercruiser with 2006 3.0 mercruiser help.

    I have a 1970 carevelle 120hp mercruiser with a mc-1 sterndrive. I am planning on getting a 2006 3.0 mercruiser engine. I know I will need to get a 12.75 flywheel and special coupler to mate up to the mc-1 sterndrive but what do I do about the following:

    1) the exhaust manifold to fit the mc-1 sterndrive.
    2) the shift cable from the mc-1 drive to the newer exhaust port configuration.


    Basically can I use a newer 3.0 engine and mate it to my mc-1 sterndrive successfully? I think my mc-1 sterndrive has a 1.94 ratio.

    Be kind everyone I am a newby. Pulling the sterndrive and engine out was a breeze. Now I need a plan to reinstall everything.


    Buck

  2. #2

    Default Re: repowering a 120hp mercruiser with 2006 3.0 mercruiser help.

    Use the manifold off the 3.0 and exhaust elbow that bolts to the manifold. The head ports on these engines changed in 1990 ish along with the one piece rear seal that is necessitating the flywheel and coupler changes.

    there are a couple of rubber exhaust boots and a down pipe that probably should line up with the newer engine. Would be a good opportunity to replace the exhaust flapper in the down pipe as well. If the stock boots donít work you may be able to use 3Ē hardwall marine exhaust hose to make your own tweaks.

    not sure where the shift plate mounted on your 1970 my1990 3.0 it mounted to the valve cover. I assume yours mounts to the manifold? Would suggest you make a bracket to adapt it to the newer manifold

    use the flywheel cover off the older engine as the mc1 will have a different rear mount spacing than the newer (post 1981) engines

    are you getting a complete 2006 bobtail? Would just make sure you keep wiring harness and distributor together off same vintage engine as older one has points and newer will have EST.

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