Depends on how much water there was in the tank -- if a lot, you have a slug of sticky syrup on the bottom and will have to remove the tank and flush it. If it was only gas in there, no water, the sugar is still granular and you may be able to flush it out with gasoline, which is safer, but I would imagine you will still need to remove the tank. Make absolutely certain that you have only clean gasoline coming out of the supply line to the fuel distributor before attaching to a new one! Else you will fry that one, too.

DO NOT use gas line antifreeze to try to get it out, it will dissolve the sugar and allow it to mix with the gasoline, and THAT will fill the engine with carbon, not pretty.

Was the head full of glassy carbon? If so, I would also get new rings and pull the pistons and clean them -- that carbon will have very likely gotten down there too, and will cause the rings to seize, ruining the cylinder walls.

Get a locking gas cap to help prevent recurrances -- and make sure the filler door lock works, too!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!