Merc Mark 5 ~ 6 Ring Compressor

[Buccaneer]

Just put my second Merc Mark 5 ~ 6 crankcase back together,
and struggled both times with homemade contraptions for
piston ring compressors. Used some aluminum flashing
on one piston and a plastic band on the other, both
trying to snug up the rings with tie wraps. It’s
aggravating keeping the ring gaps on those tiny
pins!
In looking at the manual, they show Mercury tool 91-24280
that looks like it would work slick. I’ve never seen one
for sale, so I was wondering if anyone has ever made their
own of the same design?
Anyone have a good photo of an actual one? I can’t tell
what’s going on the bottom of the compressor in the photo.
Is the band adjustable?
Thanks!

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Attachments:

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[jasonh]

The bands are specific to piston size. Not adjustable.

[Buccaneer]

Jason, are they made to "hinge open" for easy
install and removal?
Thanks

Prepare to be boarded!

[jasonh]

Yes, they hinge and come apart for easy removal.

[billw]

The almost bigger trick than good ring compressors is to make some kind of device that will hold the block and crank case more or less aligned, as the come together. This frees up your fingers to guide the rings in with your fingers nails, Popsicle sticks, etc. It also helps to be very generous with the oil.

Long live American manufacturing!

[Goman]

You may try using needle nose vise grips to lock your flashing in place over the rings. Free’s your hands up too.

[Buccaneer]

Bill, I believe the first one that I tried to assemble
I used some long guide bolts, but just ended up
getting in the way 🙁
Goman, I was thinking of something along that line,
but maybe a little fast acting clamp to hold the band
tight instead of needle nose.
Good ideas, thanks!

Prepare to be boarded!

[dave-bernard]

An old driveshaft in a vice works to hold the powerhead while working on it.

[Buccaneer]

Dave, if I work on other one of these little "Marks",
I may sacrifice one of my parts drive shafts
and weld part of the shaft on a plate that I could
clamp or screw down to the bench top. Thanks
for the idea. Just got the swivel tube back in
the crankcase housing….. will have to invest
in a press some day!

Prepare to be boarded!

[Anonymous]

just use your lowerunit and clamp the DS in a vise. no need to destroy a good DS

[Author]

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