Definitely get a new battery first... well, check all your cable connections, then get a new battery.

A dead battery can definitely make a car not start even with a jump. 'specially if you aren't using the very best of cables.

Some ATF (automatic transmission fluid) or motor oil go in the holes that appear wehn you remove the black knobby thingies on top of your carbs. Once you put a little (just a little...maybe a teaspoon or less), then your carbs should be oK.

And yes...it is DEFINITELY (fairly likely if you've had a good rain recently) possible that you ahve water in the gas. early (pre fuel injected) 1800s are notorious for that due to the silly location of the fuel filler.. that being right where all the rainwater runs. Check the rubber gasket that goes over the filler hole, and most importantly, make sure the drainhose in said filler box is not blocked.

Checking for water in the gas... have an assistant hold the fuel line so it flows into a clear glass or plastic container. Crank the engine untill you have an inch or so of "fuel". IF there is water coming in, you will be able to see the separation....

Also, as your car sits... if you pour a small amount (another teaspoon ish) of gas right down the floats of the carbs, then try to start it... if that makes her wake up...its probably water. Stand back when you do that though, in case it backfires out the carbs... and its good to have a fire extinguisher on hand just in case...or at least a bucket of water. But every SU carb equipped car owner should have an extinguisher aboard at all times anyhow.

Gas floats on water, so all the water in the tank is at the bottom of the tank, therfore, it gets sucked up first.. so, it don't take a lot of water in the tank to stop you cold. If you do have water in there, you'll have to either pump it out (keep checking, and you ain't good until there's no more separation). Or you can partially drain the tank, but that is messy.

Good luck! My 1800 has a tankful of water... I'm gonna have to drain it entirely before it runs...

-Matt