Have run into stuck pistons several times and evolved a set of tools. Just finished removing a piston from a Mercury KE4 twin. Works on all K models,
KD,KE3,KE4,KF3,Mark 7 all the Wizards based upon
this series and the Sea King singles made by
Kiekhaefer. Makes a mess, but, does the job.
Documented with lots of pictures.Am waiting to
hear if Jason wants to post. If anyone has a stuck
piston and would like me to send pictures plus
commentary drop me an email
Louis

You could post the pics on a free picture site like Flickr or photo bucket and then put the image links in your post and it wouldn't take up space on the wizard forum.

I used the grease gun technique yesterday to free up the pistons of a 1964 3HP Evinrude Lightwin. I got it as a freebie When I bought an old 1951 Johnson TN-27.
Water had been left in the cylinders and the pistons were frozen in place.
I removed the crank shaft and filled the cylinder with used oil before screwing in my modified spark plug base.

The modified spark plug is an old plug I knocked the porcelain out of. I welded the top of the base closed and drilled and tapped it for a grease nipple.

I pumped grease into the cylinder and moved the piston until oil started squirting out the ports.

After I got both pistons moved downwards, I removed the cylinder head and used a piece of wood with a slot cut in it lengthwise to press out the piston on either side of the connecting rod. this was rigged on the drill press and the chuck served as an arbor press to remove the pistons.

Note: Never remove the cylinder head before trying to free pistons this way. I broke three bolts trying to remove the head and would not have been able to use the grease gun method, had I tried to remove the head first.

This is a very useful technique and I wanted to thank Louis for sending me pictures and many emails to show me how to do it.
-Bryan

Louis Sent me this tutorial on how to unstick a piston using the grease gun method and I thought it should be posted here. Thanks Louis for the information.
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Louis Wrote:

Bear in mind situations will vary...I have burst cylinders and
a broken crankcase to show for lack my of patience with really stuck (pistons).
If it looks clean, it will very likely unstick...if it looks corroded, it might be
a good candidate for a long soak in which ever miracle solvent
you subscribe to...before resorting to extreme measures.
Lightly stuck motors sometimes respond to Marvel Mystery Oil poured
in through the spark plug and carburetor opening and allowed to set a few days...
then try to work the flywheel back and forth....worked on a Mercury KB4 and
on a Johnson TN26...never hurts to start with least effort methods and
go on to more aggressive methods as required.
Louis


Stripped twin block with stuck lower cylinder, water jackets, tools



grease gun to spark plug adapter, exhaust port cover.. & cardboard gaskets



the intake port cover bolted in place...port holes stuffed with oiled tp



Exhaust cover close fit to cylinder, paper and copper gaskets, ports stuffed



note set up on the loose cylinder and stuck cylinder ready to go



ports and cylinder are stuffed full of oiled tissue paper..to seal against leak



view of exhaust port in place..



lots of views of port covers...unless you can keep grease in... no pressure



I like direct pipe connection to adapter...hardware store bought



this is end of line with grease gun..note blob of grease piston slid down a ways



the piston is free BUT stiff ...compare gap to earlier pictures



grease gun adapter and port covers removed...

Now for part 2:


lower edge of piston just clear of bottom of cylinder but still not out



sometimes at this point this will work ...don't use metal rods...damage piston



Did not work...so....a new idea required NOW



notice how piston is edging out out cylinder



coming along nicely...needed longer threaded rods... all that I had on hand



makes a mess ,but, does the job



now to see how badly cylinder and piston are corroded....



wadded paper in cylinder reduces volume of grease to clean out and may seal leak



job went just as pictures show...had to stop wash hands...take picture...resume



a little bonus... note tools wood cradle and brass rod from water valve.



get the ideal?



a side view



not all tools are fancy store bought or machinist made...



top view and ready to remove piston pin, drive through back to front



later piston with 20 loose needle bearings & 2 washers...early had cartridge GB$


Having the means to apply great force does not always lead to
the desired result.
Each stuck motor is unique...the techniques I have shown are capable
of either freeing up or destroying a motor...patience and considered
thought can avoid damage...impatience and thoughtless actions
yield disappointment.
Louis


Being clever does not always work...sometimes you have to get lucky.
Word or two of caution...since we are dealing with the last of their species
be sure motor is a good candidate...sometimes step one should be dropping them into five gallon bucket of auto transmission fluid, seal the cover and wait six months....I might not have ruined a WB6 and a KD4 had I taken
the long view rather than going for instant results.
On the other hand I did not pay much for them. Left over parts may do some
good some day.
Louis

Thanks Louis!

Those who have access to the Mercury Service Manual
can compare how things were done on new motors
with factory tools with all the interesting details
left out. My goal is to complete the series on tear down of Kiekhaefer twin K Models (which are much the
same in both Mercury and Wizard brands.
Once taken down to individual parts a series on
rebuilding is next.
Thanks for posting the pictures, but, don't let
my wife see how I use her washing machine...
Louis

UGG! Nice hammers!!



JW in Dixie

A few important notes on removing piston pin using
this method. Haste made waste yesterday.
1)unless rings are stuck to piston remove them
BEFORE removing pin...
2)padding between piston and wood cradle is
needed to prevent damage to piston
Failure to do the above caused me to ruin a pair
of excellent pistons by breaking a ring ,
smashing down the copper pin ring locators and
mashing in the piston around rings.
Damage resulted from too little thought prior to
too much action.
3)the piston removed in this series was usable
after rings were removed(in pieces)
It took a lot of cleaning and scraping.
Rings and a better piston pin,bearings
and G clips will come from the ruined
pistons. .

Another "How Not To Comment"...last night noticed
a previously overlooked two cylinder powerhead...
a once over showed it was stuck...no problem and
had a more immediate need for the magnet rotor...
when on bench under good light it became apparent
that a prior mechanic had attempted to unstick
by use of a pipe wrench on tapered end of
crankshaft...NOT PRETTY and it would require a
precision outside diameter grinding on the taper
to clean up protruding ridges of metal to salvage
the crankshaft...not a worthwhile effort for a
not too uncommon motor.
A stuck powerhead is usually a solvable problem
that responds well to thoughtful efforts...and
usually responds poorly to hasty grab a bigger
hammer solutions.
Louis

Coild I purchase two spark plugs as addaped for zirk fitting for 1998 Mercury 25 hp ??

Mitch

I believe the greasegun adapters are available from several sources. A machinist
friend made the 14mm one I use as well as an 18mm one I have yet to use.
I think same guy that reproduces Mercury Service Tools may be a place to
start looking. Local auto parts store may have or be able to order. They come in pretty handy so I expect they are around. The captions confuse intake and
exhaust ports...don't let that bother you...go by the pictures. Port covers
especially the flat plate over exhaust ports really are needed...easy to
make the flat plate...the curved cut out cover for the intake ports is
not as important as piston usually not stuck far down bore. There is a series
of comments and pictures on JohnsOldMercSite.com of taking a single apart using a press to force piston down bore ...piston was scrap so no harm by use of press and rod thru spark plug hole. As the saying goes "there is more than one way to skin a cat"...learn to think outside the box and use what comes
to hand. On a later project I made up a set of 4 threaded rods to get a stubborn piston out after using greasegun...never hurts to lube the cylinder below the piston prior to using greasegun and/or threaded rod setup.
Given the modular nature of the early Kiekhaefer K Model outboards and provided a donor motor is available it is possible and practical to rebuild
even pretty rough looking old outboards. Worst case you get to add parts to
inventory.
To answer your question can the technique be used on later Mercury (or any
brand) outboards. Good question...depends upon construction of powerhead as
to whether ports can be sealed. If both pistons are stuck or crankshaft is
not free to turn thing may not end well. The greasegun solution works very
well with early K Models with only one stuck cylinder...it may/may not be
the right method for some brands and models. Bear in mind the grease gun
is the big hammer for otherwise mixed metal junk outboards...it often works
well but sometimes another approach is wise.
Louis