My 2 cents....FWIW....the fuel baffle in the tank has some 'typical"problems:
1) EASY...the plastic cap on the bottom of the baffle falls out thus allowing the float to fall out of the baffle so the console guage always reads empty.....you can pull the baffle out and see this easy enough...if it is so, then fish out the plastic cap and the float (you can get a long flexible 4 prong retriever from Harbor Freight, for a couple bucks...they come in handy for other stuff too).....put the float back into the baffle, put the cap back into the bottom of the baffle...probably best to melt the cap into the sides of the baffle (heat the end of a screwdriver or use a soldering iron), re-assemble and see if that fixes the fuel level issue, use the volt meter to test if the baffle is giving resistance readings as you tip it back and forth. If not, then......
2) The fuse F1 on the baffle circuit board is blown...this is technically fixable.....you'd need to cut a hole in the top side of the baffle assembly in the right spot to actually reach the /circuit board & fuse, then bridge the fuse with some careful soldering (but this will then negate the fuse as a source of protection...so your call). Melt the cut piece back to the baffle tube...no need to fill all the gaps of the baffle cuts as it is submerged in gas most of the time anyway, re-install everything and test the fuel level function.....use a volt meter to see if the float is giving a resistance reading as you tip the baffle back and forth...if not then..
3) time to replace the fuel baffle assembly itself......NOTE: the newer assemblies have 1/4" AND 5/16" nipples on the top, most older machines used 1/4" fuel hose...so this was a slight problem....I simply reamed out the inside of the 1/4" fuel hose JUST enough to slip over the 5/16" nipples....problem solved.
FINALLY....if not already done....replace all the fuel hoses from GREY TEMPO lines to standard black 1/4" hoses and might as well replace the fuel selector switch at this time. Patience is the key here.....good luck.