straight chain paraffins
aromatics
branched chain paraffins
napthalenes
brake power
compression ratio
specific air consumption
mean effective pressure
engine can run
engine gives maximum output
engine is most efficient
fuel can be used in a test engine without knocking
tool lean mixture
stoichiometric mixture
most economical mixture
too rich mixture
spark plug gap too small
spark plug gap too wide
vapour lock in the fuel only
incorrect fuel air mixture