Originally Posted by oldtimebuilder
Couple of things you may want to give a shot.
1. Pull plug on cylinder and spray WD40 into cylinder. let it set couple of hours and try see if it helps
2. do the same above but use Marvel's Mystery Oil.
One note, because you don't know why its stuck, (ie galded piston, carbon, broken ring etc.) these are the safest non invasive measures
One note, if you are absolutely sure you have to go into it, we used to mix BonAmi with water and pour it in the intake of carburated engines. Of course, we;d sell em soon after they started hitting on all 8...lol
LOL now some kid is goingto go out and buy some Ajax, Vim, Bon Ami or whatever and give it a go. We've had a lot of fun with this one over the years on another board, especially when discussing rapid bedding after a rebuild.
For my money one pot much lower than the other three = badly seating or burnt valve.
As carls47807 posted, the wet compression test will tell you if you have minor leakage from either the rings, bore or valves. I use the minor term hesitantly.