Hi this is an easy (ish) job, but must be done in a very well ventilated area or best outside. first try undoing filler cap & starting if it doesnt die on you its ONLY the hole in filler cap to clean! or...
Drain fuel tank by dissconnecting at carb with a catcher bowl bigger in capacity than the fuel tank. (an old 2 litre icecream box)
dont touch the screws on the carb- they dont need adjustment. I use a pencil to mark them so if by accident... (marker pen will be lost if contact with petrol)
under the carb bowl is a bolt head.
undo with a rag uderneath to soak up fuel that will spill.
gently move the float up & down to check its free.
inspect bottom of bowl - its where 98% of crud end up. scrub with toothbrush & scrape using bamboo screwers - dont use metal as will remove the coating & may leave filings that will end up in engine. the bowl does need to be reasonably clean .
on the end of the fuel line blow up into tank - use a foot pump or football pump (pound shops sell these for beach balls etc)
if there is any resistance then youll be looking for the blockage.
it does pay to remove the tank place a little fuel in it and swill it out. use kitchen paper as a tell tale to pour out onto - youll see it come cleaner until no bits. reasseble fresh fuel in try it. when starts put redx in allow to run for a long while at high revs.
Jerry the Fish
July 2009