To Hone or not to Hone is the Question

[labrador-guy]

Gotta get my two cents in on this one! What is you ring end gap measurement? Take a ring off the piston and push it back into the bore with the piston so it is square with the bore. Is the ring edge sharp? Severely worn rings edges will cut skin with a little pressure. If you use a hone do it lightly and vertically because it is easy to get the cylinder out of round. End gap values are usually posted in specifications. Big end gap means less compression. Motors that set for a long time will bring their compression up with some use. Use fresh gas and synthetic oils and your motor will surprise you.

dale

[Tubs]

https://aomci.org/forum/viewtopic.php?f=2&t=15662&hilit=hone#p82018

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

[Buccaneer]

Good idea on the ring "end gaps". I’ll try to get a ring in the bore and
measure the gap, but with the way this power head is built, it may be
hard to get a measurement with the ring at the top of the bore.
It’s "headless" and the jug and crankcase is all one casting.
This piston comes out of the bottom of the crankcase after the
crankshaft is removed.
It’s the type of piston that has all three rings pinned with the end gaps
lined up in a row……… that never made sense to me!
I remember reading that about honing / roughing up the rings on that
other thread…… not sure I’m ready for that one yet. 😕

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Prepare to be boarded!

[Buccaneer]

I pulled the rings off the piston and shoved one into the
bottom of the cylinder bore. I came up with .014 end gap,
which seem a little much unless air cooled engines
need more gap? I could not find specs on it.
Doesn’t the bottom of the cylinder bore usually have the least wear?
If so, my end gap could be a little more at the top of the bore.
I did not attempt measuring at the top, as I had a hard enough time
with my angled feeler gauges measuring the gap with the ring
at the bottom of the bore 🙁
There was some carbon under the rings so that could be a minor
issue with the low compression.

Prepare to be boarded!

[Mumbles]

I used either a shortened ball hone with a flexible shaft or an angle drill to do this one a few years back. Can’t remember.

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[Pondrocket]

For my 4cyl Mercs I use this hone works wonders. High quality but you need to know what your doing.
http://www.lislecorp.com/divisions/products/?product=45

Travis
AOMCI VP Communications
AOMCI Webmaster
webmaster@aomci.org

[Buccaneer]

That Lisle hone is probably money well spent for your high performance
Mercs. For my $20 outboards, most of which I’ll probably run on the boat
once and throw back on the rack, maybe not. $240 would start a spending
war with the wife. 😯

Prepare to be boarded!

[labrador-guy]

Wow it’s gonna be hard to get a good end gap reading on an engine like that. You need to check the gap above the ports in the compression area. .004" to .005" per inch of bore is a ball park figure. With three rings a little more probably be OK.

dale

[Buccaneer]

Dale, I don’t think that the ring gap is going to be "less"
at the top of the bore than the .014 at the bottom, so
I’m not going to bother trying to measure at the top
of the bore. It’s a $20 outboard, and it’s not like it’s going
to be bored over size, etc., therefore, "It is what it is"!
I’ll stick it back together and see if it runs. Maybe de-glazing
will give me a little more compression.

Prepare to be boarded!

[auldscott]

Lots of good information about honing here, and at this point it may be too late, but a classic check for bore and ring wear is to put some motor oil into the spark plug hole, make sure it’s distributed all around the cylinder, open the throttle all the way, and then run another compression check.

Art Sesselberg’s Oddjob Motors site says that the compression should be 70 to 100 psi.

[Author]

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