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Stuck Piston: My Companion to the grease gun technique

Just wanted to share a new (to me) technique that I've been playing around with on freeing lightly stuck pistons in single cylinder motors.

I got a single cylinder Brooklure outboard motor in the mail this evening that was stuck. Sorry that it wasn't another Wizard.
The motor was clean and in good condition and it was evident that it was kept dry inside a garage or barn. The piston was stuck at top dead center, as it seems like most stuck ones are near the top.

I removed the spark plug with some difficulty as it was stuck pretty tight too.
Once the plug was out, I poured in a little of a mixture of transmission fluid and acetone and let it soak a couple of hours.

After supper, I put in my "homemade spark plug"...a spark plug that had it's porcelain insulator knocked out, the hole welded up, and smaller hole drilled in it's place.
Instead of a grease fitting in the hole, like Louis uses, I have the metal part of a tire valve stem soldered in so that I can inject compressed air into the cylinder. I pumped up the cylinder to about 100 psi. and started turning the flywheel by hand. The air pressure forced some lubrication past the rings and pressed the piston downward. The motor freed up almost at once. I thought I'd try this first to see if it would work and was planning to use the grease gun technique if it didn't. I have good compression now and I feel I can forgo tearing into the cylinder to remove grease.

Please Note: I would not try this with a cylinder that is unbolted from the rest of the motor as something has the potential to become a projectile pretty fast.

If you don't know what the grease gun technique is, you can find the post HERE.

Re: Stuck Piston: My Companion to the grease gun technique

Just as there are different wrenches and screwdrivers each more suited to
one application than another so too there are several approaches to
unsticking an engine. Several of my stuck motors had results greatly different than desired. Oops does not evem begin to cover the situation (children cover your ears.)
Always nice to hear about good results and alternative methods.

Re: Stuck Piston: My Companion to the grease gun technique

Yesterday, I was cleaning an old Elto Ace carburetor that has a sort of poppet valve inside of it. The poppet valve was completely glued shut from varnish deposits caused by the gasoline left in it ages ago. As I recall, oil in the first part of the last century was paraffin based that could leave a waxy residue and that varnish build up from old gas was a threat until the introduction of ethanol in modern gas.

I dissolved the varnish by rinsing the parts in a cup of Heet.(gas-line antifreeze and water remover composed mostly of Isopropyl alcohol.) I probably could have used denatured alcohol or corn liquor, for that matter, with equal results.

Getting to the point:
I was wondering if some "stuck" engines could be stuck from varnish deposits gluing the rings to the cylinder wall instead of the usual culprit...rust.

If my hunch is true, I think that a little bit of denatured alcohol along with the transmission fluid through the spark plug hole, could help free up the piston easier in "lightly stuck" motors.


Re: Stuck Piston: My Companion to the grease gun technique

Another chapter in the grease gun story. I have been working on a stuck Mercury
KF7 where the stuck piston was just above the exhaust ports. I got the piston to
move down until it leaked grease at ports. Then switched grease gun to other
cylinder all that did was twist the cylinder block (KE7 and later models in series have cylinder block bolted to crankcase)in relation to crankcase. The crankshaft is frozen in position. Wood shims driven between crankcase and
cylinder block did not increase 3/8" from greasegun.
The 6 studs between cylinder block and crankcase were easily removed once a 3/8" gap was available to use thin vise grip on plain part of stud. Replacing the studs with 6" section of 5/16" threaded rod made it possible to use nut and washer to jack the cylinder block and crankcase apart.
It is not yet done so I can not say yet if it is worth the effort as everything may already be junk or damaged in process. The project came as a gift and it is at least a "learning curve"experience if nothing good comes from parts.
Several Kiekhaefer made Wizards use same or similar powerheads so technique
is relevant and possible helpful.

Re: Stuck Piston: My Companion to the grease gun technique

Jacking crankcase from cylinder block worked as hoped. Pistons appear undamaged
Bearings on piston end of connecting rods move freely. That is the good news.
The BAD news is rods are rusted to crankshaft with lots of evidence of water
plus time equals rust. The jacking was accompanied by loud groaning sounds.
The screws put a tremendous pressure to bear on whatever was resisting movement
Cost of tools...3 feet of 5/16" x 18 Threaded Rod $3.01, 6 5/16" nuts and washers
$1.23 = total of $4.24 plus 5 dremel abrasive discs consumed in cutting rod into
6" lengths. Ends were ground and used a die to clean up threads.
Tools may come in handy again someday or more likely evolve into some other