Whats the inlet side look like???
The shot of the top of the piston would have been better if the piston was at the bottom of the bore so we could see what the bore is like.
That would go in my work it out later pile, i couldnt sell a mower that looked like that inside even if it did run.
Having said that, there is a good possibilty that it would still run. (depends how bad the inlet side is. Looks like the exhaust side is well and truely stuck in the piston)
So its probably worth testing further even if its just to work out the value of some of the other parts.
Spark is ok, the coil is good.
Fuel delivery, check out the carb and if its good to reuse.
Working starter.
Head thats not warped. (this combined with the piston like that will stop it running for sure)
You would probably find that if you remove the piston and the rings were not too difficult to get out, the piston could be cleaned up with some sand paper, wet rubbed with WD40, clean the ring grooves out and fit new rings hone the bore and it will work fine for many more years to come.
Or fit new piston and rings.
Before i get bagged out for being rough. For a mower for myself i would do and have done in the past. Its just a mower, its not a light plane engine, or a motorbike. If it does let you down thats the perfect excuse to kick it and go inside and grab a beer or 10 come back out and sit in a chair and try and talk to it about its problems. Sorry not an option for you at 15.
Its a basic engine design, to work right it needs to be spot on, to just work, its basicness is in your favour and theres lots of forgivness in the design.
Test the spark as mentioned above and try some 2 stroke fuel in the plug hole, see if it will at least give a cough.
Probably little point now seeing as you have the head off.
The crank seals. The top is the o-ring under the starter. In the bottom its part of the bearings. Its a special bearing made for Victa Power torques, it is open one side and has a heavy duty seal built in on the other side.
To go any further with that motor you will need to obtain or make a special tool to undo the conrod bolt.
