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Setting the Timing on a 1978 Mercruiser MCM 140

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  • Setting the Timing on a 1978 Mercruiser MCM 140

    I rebuilt a 1978 Mercruiser MCM 140 and got great help from this site. I am all done, it runs great, but I want to set the timing so it's perfect and I can enjoy it without worrying about it. Ignition timing is supposed to set at 6 degrees BTDC. I can't find the line I'm supposed to see (lots of scratches & such). If I take the distributor cap off and turn it to position 1 will that make it easier to find? Can someone give me the steps on how to set the timing right, after I find the mark? I do have access to a timing light. Thanks for your help.

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    Re: Setting the Timing on a 1978 Mercruiser MCM 140

    Take out plug #1 and turn engine until #1 is at TDC on the compression stroke. Your rotor should be pointing towards the #1 wire on the distributor cap. Now look around for your timing mark. Use a piece of emery cloth to sand around lighly and the mark should appear. Paint the mark with paint or white-out correction fluid (LOL No one uses it anymore).Time to your hearts content.Bob
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!