Hydrochloric (Muriatic) Acid can be used for this. It is a mild acid,but still acid, so use care. Using an acid brush brush the acid on the aluminum, depending on the thickness of the aluminum it can that a while, but will remove all aluminum from the cylinders without causing any problems. The fumes can be rough, so ventilation is important. I have used this for years to save engines , so they can be repaired.
It could be many things. First thing I would do is get your carbs removed and clean them up. Next, I would clean your powervalve/exhaust valve ( if your model has them ). If still not doing any better, check your compression. If all cylinders above 110psi, clean your clutches.
Clean plugs new ones maybe new points
You can clean the aluminum particles by dusting them away.
Collect all the necessary parts. Clean the parts. Install piston rings on the piston crowns. Smear engine oil on the piston cover and the cylinders. Install the rods and the bearings. Add grease to the bearings and seal them with caps. Connect the rods and pistons to each other. Insert the rod end to the engine block. Connect the timing chain. Apply a new gasket and install the head plate.
To remove both oil and grease you should clean aluminum with a solution of water and mild dish washing liquid. Generally, aluminum items around your home just need a good periodic dusting with a soft, clean cloth, to keep clean and shiny. Thanks!
wash and polish it
Ammonia can be used to clean aluminum, but it may cause discoloration or damage to the surface depending on the concentration and exposure time. It is safer to use specialized aluminum cleaners to avoid any potential harm to the metal.
to clean unspent fuel out of the cylinders
try using baby oil
You can use a power washer to clean aluminum pontoons. The power washer will remove most of the dirt. To remove additional discoloration you can use a product such as Barkeepers friend.
To effectively clean aluminum using vinegar, mix equal parts vinegar and water in a spray bottle. Spray the solution onto the aluminum surface and let it sit for a few minutes. Then, scrub the surface with a soft brush or cloth to remove any dirt or grime. Rinse the aluminum thoroughly with water and dry it with a clean towel.
Most people consider aluminum blinds the easiest to clean.