Redex is 90% paraffin (aka kerosene) and is a bit dear for the red dye.
Go to Homebase and buy a 2 litre bottle of their "Turpentine substitute" (n.b. not White Spirit which is sold next to it, in an identical bottle) for about £3.
Stick about 200ml into a full tank of fuel. Go for a good trip but you don't necessarily have to rev the sh* out of it.. paraffin dissolve gum and varnish just by being in contact with it.. engine revs don't add anything extra to it.
After the first tank, use slightly less .. about 150ml per tank regularly, just to keep any new gum under control..
Ralf S.
