something you should check mate,
did you use the correct gasket under the bulb plate?
the rebuild kits cover various carbs and there are two gaskets in there that are almost the same, (i think i remember right that you have a 668)
one has a cut out and one doesn't at one end, use the wrong one and you get no pumping to fill the bulb,
(ask me how i know ),
as for the internal filter, do ya mean the round screen ? if so that screen is very fine mesh and crap usually tends to gather outside only, just needs a blast off with brake clean normally and its good,
if ya removed it, did ya refit the new one that came in the rebuild kit ?
did you use the correct gasket under the bulb plate?
the rebuild kits cover various carbs and there are two gaskets in there that are almost the same, (i think i remember right that you have a 668)
one has a cut out and one doesn't at one end, use the wrong one and you get no pumping to fill the bulb,
(ask me how i know ),
as for the internal filter, do ya mean the round screen ? if so that screen is very fine mesh and crap usually tends to gather outside only, just needs a blast off with brake clean normally and its good,
if ya removed it, did ya refit the new one that came in the rebuild kit ?