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    1976 850 runs on upper 2 cylinders

    I have 1976 mercury 850 that's only running on the top 2 cylinders. Lower 2 have spark and all cylinders have 145 psi for compression. I've tried cleaning the carbs twice now but nothing I have done will fix the issue. Removed the power head and started tearing it down. Just as I was going...
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    1976 mercury 850 thunderbolt running on top 2 cylinders

    Hi, I'm fairly new to the forum and to outboard engines. I got this boat for free and it would start and run fine with the muffs on it but as soon as I got it in the water it had no power at all and would just die when engaging the prop. My problem is it only runs on the top 2 cylinders. Cleaned...
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