Zoltan,
Just spraying it with carb cleaner. The connecter end has an opening between
the contacts which, unbeknownst to most, you can access an adjustment screw.
First remove a set screw with a 1.5mm allen(if memory serves me) then use a
1mm to adjust. If you pull back the rubber boot the adjustment is possible
with the engine running.
Ken Lewis
http://neksiwel.20m.com/