So for oversized rings in an outboard do i have to bore out the cylinder wall first? Or are you supposed to not bore it. Could I hone it to the right size?
Well could i just hone them out till they will fit rings that are .030 over? Its a 15 hp 1990 johnson thats in question. It overheated and has low compretion
With over size rings you'll need over sized pistons. If you haven't got the proper hone you will never get the cyl accurate. Best thing is going to a machine shop.
As Boobie said you must have oversize piston to match rings, and you cannot use a hone to bore a cylinder oversize as (1) a hone removes little material (2) you cannot keep it round. The only way to hone it oversize with a hone is a Sunnen honing machine like in a automotive rebuild shop...
if you take it to a rebuild shop they will measure the bore to see how out of round it is and whats the min they can cut to restore the cylinder. (they might even do this with just the head removed if they are friendly) you might get lucky and have just toasted the rings then all you would need is a cross hatch and a new set of standard rings.
dont order the pistons first until you know what size that is required.
