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  1. #1
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    Merc 200 Compression

    Why would a 1997 Merc 200hp have compression of about 110psi on all cylinders and a 1998 have about 125psi on all cylinders? Was there some porting change between the two years, or is that just a sign of wear on the lower one? Does it mean the higher one will run better and have more power?

  2. #2
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    They are both within factory specs. According to the manual. Although, 110 is at the very bottom of the range.

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  4. #3
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    I didn't take the reading, but I bet it was taken cold. Would you trust buying a motor with 110psi like that?

  5. #4
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    we found over tha years its best ta have more than one gauge if ya don't have one thats proven (trust)... 110 on all tha holes of a motor thats that old, would take a chance on it myself for tha right money... jmo

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  7. #5
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    I have a 2000 200 carb motor I just rebuilt. Has about 30 hours on it. It has 120 PSI. I also have a 2001 200EFI I have been working on. It has 108-110 on all. A leakdown test says only 3% loss. I would say 110 on all is good to take a chance for the right price.

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