REALLY old gasoline consists of residual dye (gas is actually clear --
remember "white gas" for Coleman stoves?), detergent, and the heavy
ends (diesel fuel). Badly evaporated enough, and it won't even light
with a match! Needless to say, it won't burn worth diddly, nor will
the engine start without some help.
It also reacts with brass to make oxidized slops and can even (although
I've only seen it lately in very old engines) varnish -- sheets of
clean, plastic like stuff that looks for all the world just like the
skin off the varnish in a old can.
Try draining out the old fuel (or filling up with fresh) and see if
that helps.
Peter
