The first thing to do when re-building the carburetor is to strip it down. Take lots of photos of it if you feel you will be unsure of how it goes back together but in reality it is hard to get it wrong as no part can really go into the wrong place.
The first thing to do is find a large clean and steady table. You will be dealing with a lot of tiny parts so you want to make sure you have a surface with a nice light colour so you can't misplace anything.
While disassembling the carb it is a good idea to lay all the parts out on your table grouping like items together.
In our case we re-plated every metal piece back to the original yellow zinc finish and all metal parts were cleaned in a chemical bath of carburetor cleaner. This fluid is fantastic at removing old deposits as it is essential that everything be surgically clean before re-assembly. To do a proper job you must have a source of compressed air to test that all passages are clear. If you do not have a compressor, a can of pressurized air (used to clean computer keyboards and available at any office supply shop) works well.
You will also require a re-build kit. There are many on the market and by far the best is the one from Pierce Manifolds www.piercemanifolds.com . It is very complete and reasonably priced at less than $50 per carb. Other kits cost less but have much fewer parts so this is worth the extra expense. Do not be afraid of having left over parts as the kit is very comprehensive and has pieces for multiple carb models.
With all of your pieces clean it is time to inspect everything. Using a straight ruler check to make sure that all machined surfaces are flat. There is no magic here and all it takes is patience. Also look for anything that appears off and check to make sure that the throttle shafts are straight by rolling them on a flat surface. If they roll easily then they are straight.
Extensive cleaning is not about being obsessive. The time spent with a part during cleaning gives you a chance to really have a close look at it to try and locate damage, cracks, and faults that can cause problems later on.
An essential tool when working on the carbs is a magnifying loop. With this simple tool you can magnify the tiny holes in the carb passages and ensure that they are clean and clear. At this time it is also a good idea to record the markings on all of the jets and tubes in the carb. Your re-build kit will come with a parts diagram which will name all of the parts.
In our next post we will get started on the re-assembly of the carburetor.