Mariner 4hp loses power in gear

hcommunications

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Joined
Aug 1, 2008
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1
I have an 87 Mariner 4hp long shaft.
Out of gear it revs fine. Putting it in gear and reving it will only get to mid speed.
I have changed plugs, rebuilt the carbs twice, pulled the lower unit all apart to make sure that nothing was binding (and nothing is binding).
What is left to check for this lack of top end power?
 
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