If it is congealed castor oil then place it in the oven at 225 degrees for about 15 minutes. It will liquify the crud and you can flush it out. It never pays to strip an engine needlessly. You will ruin the wear pattern and in general you are starting over ABC or otherwise. The engine is simple to dis assemble. Take the liner out and the piston will slip off the crank pin easily. Just make sure that you have the rod to the back of the piston when removing