Re-ring an engine?

[TheRookie]

I have a rebuilt Mercury 300 engine with 20 hours on it. It has good compression on all cylinders but when I do a leak down, one cylinder is at 10%, the others are at 4% to 5%. Will that cylinder improve or can I re-ring it somehow?

[rude tim]

My thinking is unless you are drag racing with real agressive porting, by the time you need rings your ring glands are beat and you need to replace the pistons.

[eli]

Pull the head ,front take out piston,rod assembly give a slight hone and new rings .put it back together go have fun,I do it all the time

[johnboy 88 vegas]

Run the crap out of it and try again....unless someone halfa**ed it they should all be pretty close. Sometimes they don't all break in at the same rate so be patient.

[CircleHook]

Pull the head ,front take out piston,rod assembly give a slight hone and new rings .put it back together go have fun,I do it all the time

Are you pulling front half off block?

[TheRookie]

Where do I get a hone and can I buy rings for just one cylinder?
Pull the head ,front take out piston,rod assembly give a slight hone and new rings .put it back together go have fun,I do it all the time

[eli]

Are you pulling front half off block? no not front half just plenum ,reeds to get at con bolts

[eli]

ebay or parts store about 20$ 180/220 grit light oil give few strokes 400/500 rpm
cross hatch clean up bore assemble ,ring pro marine, john marles ,merc dealer

[Capt.Insane-o]

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[eli]

180 or 220 does not matter dont do ball you can nick a port,put ring in 1/2 inch check gap no tighter than 14 top and bottom any less file a little chamfer edges i,m not a professional builder but i build alot of motors and fix many ,not just outboards