A4's have either a mechanical or an electric fuel pump. Take a look at Moyer Marine (moyermarine.com) if you would like a photo to see what they look like.
If you have an electric pump, remove and route the fuel line from the motor to a gas can, pull the coil plug out of the distributor cap, and turn on the motor. An extra piece of fuel line will come in handy, as well as a couple of extra gas cans, should you have a relatively full tank.
If you don't have an electric pump, a siphon is your best bet. Harbor freight sells them or you can find one in for fish tanks in many larger stores.
I would recommend bringing along a clear container and putting the first liter or so in for inspection. Look for water settling to the bottom and check the fuel for color. If it looks pretty good (no water, no particulate matter, not dark and varnished), I'd try to run it. A4s, like tractor motors, can handle somewhat old fuel, if it's been well kept.
With older boats, the fuel lines won't necessarily be USCG-reg hose. New fuel line is easy to install and USCG reg hose will be something on any surveyor's list.
Finally, take the time to replace the other wearable items (cap, rotor, plugs, points) and clean the carburetor before you get too excited. Any one of those can still make your motor run rough or not at all.
A well-kept A4 is a wonderful thing and not to hard to achieve.