pour 1/3 atf (attomatic transmission fluid), 1/3 acetone, and 1/3 diesel into the cylinder.
That mixture will probably work for almost anything that requires a penetrating oil of some sort. I found some info on it from some other online forum:
Machinists Workshop Mag published some information on various penetrating oils that I found very interesting. a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a scientifically rusted environment.
*Penetrating oil ………. Average load*
None ……………………… 516 pounds
WD-40 ………………… … 238 pounds
PB Blaster ……………….. 214 pounds
Liquid Wrench …………… 127 pounds
Kano Kroil ……………….. 106 pounds
ATF*-Acetone mix……………53 poundsThe ATF-Acetone mix was a home brew mix of 50 – 50 automatic transmission fluid and acetone.
Note the home brew was better than any commercial product in this one particular test.
That mixture probably works for anything where you need to remove rust, penetrate carbon buildup, and pretty much anything else along those lines. It will be my go to the first time I have to free a piston or rusty bolt or clean a really gunked up carburetor. I have not had to do much work along these lines with any of my engines; however, that mixture is what I know one of my friends, who while not particularly into outboards, knows more about engines than anybody I have ever met.
"Outboards seem to multiply exponentially..........I find that for every finished project, there are two more waiting to be completed."
