Same principle as Willie's suggestion, but disconnect the fuel line from the engine and put the end in a container. The end of the fuel line must be lower than the bottom of your tank, so you may need to add a few feet. The lower the free end, the better the flow will be. Squeeze the primer ball until you get flow started. Then let the siphon do the work. Make sure you have enough containers to collect all the contents. This won't get 100% of the contents, but it should get you down to the pickup intake.