find the fuel filter.on top is a plunger.depress this untill it begins to stifen up.this will manually prime fuel from tank.if engine starts on key then ur problem IS self syphoning and u need to replace the fuel filter/primer housing com[plete.the housing contains a nonreturn valve which is malfunctioning.couldnt tell u how many of these ive replaced over the years.filter and housing availiable form good motor factors.
caine
June 2008