Chino(is vancity = Vancouver?), there are only 3 things you can do right now :
1. buy a book recommended, like "How to Modify..." book jmortensen mentioned which is a better idea because it gives you a range of settings that is suitable for the L-series engine. In my opinion, the How to Modify Your Datsun.... book is not enough because it only tells how to set up the carb but not how to diagnose/rebuild/fix it.
2. Pay a chunk of money to have someone tune it for you because Weber/Dellorto/Mikuni sidedrafts are the most complicated carburetor system, EVER. It is impossible to solve a problem on these carbs by talking to someone over the internet, especially when you don't know enough about these carbs or when you don't have a reference book to look at.
3. Switch to SU or EFI, sell the carb setup for a good chunk of change.
I am going to do a swap from EFI to triple carbs soon. I bought my Weber books before I bought a set of Weber carbs. Now I almost finished reading the book but the carbs are not even delivered yet.
If your car is running rich like hell ALL THE TIME then this could be happening
-The fuel pressure is too high. Again you need 3~3.5 psi
-The float setting is too high
-The choke is on (I don't know if there's a choke on your carb, ppl may or may not install it)
-The jettings are rich
also check accelerator pump, this setting can waste a lot of gas if not setup properly.
To repeat myself again : These carbs are the most prestigious but also the most complicated. You need to study a book or two. Don't be afraid of carbs, the float system of a carb actually works like the water refill system of a toilet.