Reply To: 1975 Mercury 7 1/2 HP Spark Plugs

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October 30, 2023 at 3:42 pm #282149
David Stanton
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    Thanks, necks, for the info. I’ve fixed several of these 7.5s and 9.8s for friends and neighbors and I agree – best way to adjust idle is on a boat with it warmed up and in gear, but I get them running initially in a tank so I know they will start on a boat. I have a 1975 to 1978 factory shop manual, so have all the procedures. The motor I posted about wouldn’t stay running with surface gap plugs, so I think I’ll leave the J6’s in it.

    I can adjust idle on Johnsons/Evinrudes in a tank easily ( I have over 50 of them) , but a lot of those Mercurys fight me!
    Dave