I did my DMSA not too long ago.
There really isn't too much different to say about this carb than any other.
So most of my suggestions are general.
READ UP ALL YOU CAN BEFORE YOU START.
Knowledge is power. Go to Artigue's web site and get all you can.
http://www.artigue.com/fiat
His downloadable book, FIAT 124 Spider Engine Maintenance and Modification is invaluable!!!
This book will show you how to set the carb back to factory setting when you are putting it back together.
He also has PDF blow ups of many Fiat carbs, including the DMSA. Print them out and have it with you when you work.
Learn as much as you can before you start. Someone has probably been inside your carb before. Things may not always be done correctly.
TAKE LOTS OF PICTURES.
That is the biggest. You may need them as reference when trying to figure out which hole does this particular jet fit into.
TAKE YOUR TIME. THIS IS NOT A RACE.
If you get going too fast, you may forget to do something. Take your time to really see what is going on when you take it apart. Try to destroy as little as possible of the old gaskets when taking them out. They can be used to match up the new ones. Carb gaskets are easy to rip if you are not careful.
Watch carefully how the choke linkages go together.
The needles and jets need to be put back into the exact holes they came from.
Inspect all parts to make sure they are not cracked or broken.
Lots of pictures, right?
TAKE IT APART OVER A TRAY TO CATCH ANY LOOSE PARTS OR GUNK THAT IS INSIDE.
There are a couple of brass nipples that are fit into the inside of that carb. They be loose and fall out if you are not careful.
It is not fun looking around in the grass for them. (don't ask me how I know. ha ha)
USE A DUNK TANK TO CLEAN THE CARB.
You can get them for under $40 at any parts store. It looks like a gallon paint can with a little tray inside.
You can leave parts in there for hours to dissolve all of the bad stuff.
(This stuff will dissolve rubber o-rings so be sure not to put any in there.)
You CAN NOT use any kind of scraper or wire to clean the jets or needles. This will ruin them.
Only use the soaking material, spray carb cleaner, or compressed air.
Spray carb cleaners are nice but sometimes do not get out the all of the varnish, dirt, and rust that may be in there.
But you will use the spray carb cleaners after the dunk tank to blow away anything that is still left.
All of the pieces of the carb will not fit in that can. You are going to have to do it in batches.
Take notes to know what jet and needle go on which side of the carb. (Left, right, primary, secondary, upper, lower, etc)
You are taking your time, right?
CLEAN ALL SEALING SURFACES VERY WELL.
Use a razor or gasket scrapper to get all stuck gaskets off. Be VERY CAREFULL because the carb is made of aluminum and you can shave off that too (or a finger) if you are not careful. But if there is old materiel left on these areas, you may not get a good seal on the carb.
PUT IT BACK TOGETHER SLOWLY.
You are going to be screwing brass and steel into aluminum.
You want things firm and tight but do not go overboard with those screwdrivers and wrenches.
Make sure everything is exactly the way you want it before you go on to the next part.
Is the float set just right?
Are all of the jets in the right place?
Taking your time, right?
ASK QUESTIONS IF YOU ARE NOT SURE ABOUT SOMETHING.
Believe it or not, you are not the first person to do this.
There are many people (most more knowledgeable than me) that can answer your questions or send you a pic of what it is "supposed to look like".
We have all been there at one time or another and are usually glad to help out.
Please do not be intimidated by all of this. These are just suggestions that run through my head whenever I go through a carb. It is not "rocket surgery" if you take your time and do it right. If you do it correctly, this may be the only time you ever have to do this with your carb.
Let us know how it goes.
Oh......, and don't use any modeling glue!!!!
Dougieb
