Hi, If you go into Ebay & enter walbro wt-526 in the search box it should find some examples! If not & it says '0 found' scroll down the left hand side of the screen to the 'location' box & click on 'worldwide' & click on search again, you should find several examples in the USA.
I doubt if you will find a wt-24 as I think they have been obsolete for a long time. But firstly I would double check your carb, it should have the model no. stamped on it, probably next to the fuel intake. So if it is a wt-24 & you think it is a fuel problem & have checked the other possible causes it may be worth trying a replacement. My machine is a Mk1 (1986), not sure if later models were different....regards