if you look down into it, then you NEED to see fuel
(that's the fuel reservoir, a tiny seperated section of the tank.. basically the fuel bowl on an ordinary carb)
IIRC the carb diagram correctly (forgive me since I cannot seem to find the manual on my drive currently so all info is from nothing but memory)
first check that you have not swapped the tubes they have two different length for a reason
Make sure you heven't covered the breather holes wich sit in the flanges of the carb.
I cannot recall which one is the "uhh look we have a syphon" but basically once said is is locked and the vein is filled with fuel it constantly spills fuel into the venturi as long as there's fuel provided from below even if the engine is shut down.
I think there was another problem with these pulsa jets... IIRC as soon as the tank is airtightly sealed you coud either have no fuel whatsoever orrr worse, as soon as the fuel heats up (thanks to it being so close to the cylinder and exhaust)
it'll get pumped into the venturi just by sheer pressure in the tank (especially bad if the tubes are mounted the wrong way around, since not only the reservoir will be drained, but the whole tank!)
So, remove the tank cap and just cover the tank with some cloth and a rubber band to hold it in place;
if the problem's gone with such setup, all you need is a different tank cap (one that's not airtight of course)
'sid
