It is surprisingly easy to do, but there are some things to know in advance. Firstly try to turn the prop shaft as little as possible until you have it disassembled (The dirt in the engine can score the liners, etc.).

When you disassemble, you need to remember a few things:
a) How tightly wre all the screws installed
b) The cylinder head can probably go on in two directions (facing forward or back). Make a mark on it so that you re-install it in the same direction later.
c) The piston can probably be installed in two directions (at least with the OS 46FX is can). You want to make sure you install it the same way it came out. On the FX, the Con Rod is not symmetrical front/back. Write down which way the con rod was "facing".

To Disassemble, first hold the whole engine under running water (under a tap). wash off as much dirt from the outside as you can with an old toothbrush.

Remove the carb and dump it in the fuel in the cleaning container. Leave it there.
Remove the back-plate of the engine and dump it in the container.
Remove the cylinder head, find a reference mark so that you can keep it in the correct orientation later. Remove the glow plug and deposit it in the container as well.
Be careful with the gaskets and o-rings you come accross. Just leave them in the container through.
Without removing anything else, rinse out the engines as best as you can.
Then, turn the crank so the piston is at it's lowest point. Then turning the crank to help, pull the cylinder sleeve out of the cylinder. You can get a finger inside into the exhaust port to help. The sleeve will be quite tight, but it will simply pull out of the engine. Also, there is a pin so that it can only fit back in one direction.
With the sleeve out, you will find that you can disconnect the con rod from the crank shaft, and remove the piston/conrod and the crank shaft.

The only things left now are the bearings, and the con-rod connected to the piston. I would not do any more disassembly. You can clean as-is.

Using a toothbrush and fuel, clean everything. Rinse and scrub the bearings in the engine until they turn without any "grittiness".

The carb is "finnicky". I can not get a sense from the AX's manual how to remove the barrel. Typically there is a screw at a funny angle on the carb. (with a spring on it). Unscrew that screw and the whole carb barrel will slide out. There is a spring in there so be careful. Ahhh, gound the exploded view. In your manual, remove screw "5" from page 28. This will release the barrel. You can clean everything without further disassembly.

Again, use fuel and a toothbrush to clean.

Re-assemble in reverse order, making sure the piston and cylinder head get re-installed in the same orientation.

Make sure all screws are tightened to the same degree as they were originally.

gus