ok after 10 years in the shed (yes ten) and god only knows how many rebuilds, the gk71f is finally running so took it for a quick spin, all started ok but then started to sound a little bit rough so back to the man cave and out with the spark plugs one was clean (no4) the outher 3 were black so ladies and gentlemen ideas please on cleaning up my combustion chambers please, all sugestions gratefully accepted

Aj

alangjones wrote:one was clean (no4)

How clean was it? maybe not firing and just been washed by petrol? The black ones sound like it could be too rich. here are some examples of plugs and problems http://www.spark-plugs.co.uk/pages/tech ... gnosis.htm

the clean one looked normal the others were the same as the dry fouling ones only with more soot

You have the correct plugs in, and the choke is not stuck or anything? maybe forgot it on or something?

If you are sure about the above, its could be a carb / electrical fault.

Have the carb o rings been replaced? It could be leaking neat fuel into the engine as the o rings aren't sealing properly. Might be worth checking the pilot screw settings as well.
Dobbs