Dennis Country

Dennis Country

Welcome to my blog ...

Please send me an email if you wish to leave a comment. My website includes sections on the environment, green woodworking and some industrial history photos from Gwent, UK.

Decarbonising a Small 2-Stroke Engine (Decoke)

ToolsPosted by Dennis Hopkins Sat, January 06, 2018 02:50PM

An old brushcutter engine had carbon deposits in the top of the cylinder and piston, and in the exhaust port. It was decided to try to remove this because any dislodged pieces might damage the engine. For this I used some carburettor cleaner (Holts) which slightly softened the carbon, a perspex scraper and fibreglass tip "pen". Of course it's essential not to damage the cylinder or piston (especially sides), so using any tools harder than aluminium isn't recommended. The perspex is quite hard, part of an off-cut, and can be cut to shape with a hacksaw. The fibreglass "pen" is usually used to clean circuit boards etc., but worked well as a second stage tool here (the fibres are a health hazard to skin, eyes).

After a couple of hours most of the carbon was removed, except for some very hard material at the top of the cylinder, some of which was embedded in pit-damaged areas which will have to stay as it is. Some 3000 grade emery paper was used to lightly polish the piston (after photo was taken). The engine seemed to run smoother after doing this, but it could be my imagination ... at least it ran.

The main tools used