well, had the tank boiled out, and a fresh filter sock. soaked the carb in the paint can o' solvent. turned out real pretty. a few hours later same problems. fuel filter goes dry, and it runs out of gas. well god damn it i nailed it down to the carb, because i filled the bowl up with gas, disconected and hooked up the fuel filter to a length of hose leading to a gas can. with what gas that was in the bowl i had about 3 or 4 minutes of running time. the problem is not the fuel line, the pump or the filter, because it was slinging gas like mad into the gas can.
im hoping that this is just from what little varnish may have been in the fuel, or line and gummed up the carb again, and one more soak in the solvent can will do the trick.
it must be that. the stumble went away for the first hour or so. now step onthe gas hard at idle, and it will cough and die if you dont let up again.

my best guess would be a sticking float valve, BUT.... i used a small length of copper wire to push the float down, and it relieved the pressure from the fuel pump spilling gas everywhere out of the top, then closes properly when the wire is taken out. maladjusted float? i used the guage supplied in the gp sorensen carb rebuild kit, and it came with a brand new needle valve for the float...one more soak inthe solvent, and a can of gumout in the filled to the brim gas tank. crossing my fingers. i would take it out on the highway to burn the whole tank dry, but would be worried about it being starved for gas in 80mph traffic.

ok smack me... it's been a cracked exhaust manifold blowing heat RIGHT under the bowl...
problem solved?

You said the filter goes dry - I don't think a carb problem can cause that. When you tested with having it pump fuel into a gas can, you it was slinging gas - it should be a fairly constant flow like water from a faucet. If I made a few guesses I'd say either there's a problem with the fuel pump, or the lines - either from the tank to the pump, pump to the filter, or both. Since you've done stuff to the tank and carb I would eliminate them as possibilities.

Steve G.