I'll be glad to get help you out, but would be sometime before I could get together with you due to this heatwave. I am an A/C Refrigeration tech and I mostly work on the Northshore and New Orleans so you can imagine how busy we are now.
Carbs aren't all that bad. If you can get them off, you can succesfully rebuild them. If it's leaking gas out, I would guess that the floats are probably saturated and sunk or there is some trash in the needle and seat.
Anyway you will find much good advice here and these people have helped me tremendously with my lower unit problem. While you are waiting for the gasket kits to come in, go get a service manual for your motor. It will give you a better understanding of what you're dealing with and gives step by step instructions. I do consider the Johnson carbs a little harder to tune right compared to my Mercury because you have to set the idle mixture screws. Mine are fixed jet carbs, so they either work or don't.
My tips from rebuilding my Johnson 60HP carbs is this.
First scribe a I, II, or III on each carb on the side of the body AND the bowl so you don't get them mixed up as you are taking them off.
Keep all the needle valves and any other small parts that are going to stay with the carb with it's own carb.
Before you remove the needle valves, count the number of turns in clockwise until it is seated, write that number down and then turn couterclockwise and remove them.
Have a big table and lay everything out in order as you take it apart and take pictures with a digital camera as you go. Pictures are worth a thousand words or a few hundred dollars!
Set the floats per the instructions, DONT just throw them together and eyeball it!
And remember, you can do it.