Usually the cylinder will have to be pulled up and out of the engine case before the connecting rod can be lifted off the crankshaft. You should mark the rear of the connecting rod before pulling it off if there is not any marks already there to be able to put it back in the same direction. I have never had a evolution engine before but on most engines the proceedure to disassemble the engine are as follows:
1. remove backplate and head
2. pull cylinder liner out of engine
3. pull connecting rod off crank shaft and remove piston and connecting rod together
4. remove thrust washer plate
5. push crankshaft rearward through bearings and out of back of engine
6. (if removing bearings) remove carb and heat engine cranckcase in oven at 300 deg for 10-15 minutes and remove from oven and tap engine on rear and rear bearing should fall out.
7. use wood dowel from rear of engine to knock out front bearing if it does not fall out.

If the engine is really rusty inside, the cylinder liner might be hard to get out. I usually have to soak the engine in a old crock pot full of antifreeze to get some stuck liners out of the case. Sometimes just heating up the case in the oven might loosen some of the crusty oil to break the liner free. I only once ever had to build a liner puller to get a stuck liner out of a case before and that was a machining defect that caused that liner to stick.

Also, if you had black goo in the fuel lines, you should remove the fuel tank and disasemble and clean well, replace fuel tubing, inside and out, and reassemble before trying to start it again.

If it is a ringless engine, it is an ABC or ABN engine and the piston should be tight at the top of the stroke. This loosens up when the engine is at operating temperatures. If the scratches are light, that is probably normal.