How To Completly Teardown A Weber Three Barrel Carburetor.

Weber Three Barrel Carburetor

The weber 40 IDA series carburetors have been used on many models of cars and are a great carburetor. Finding a set sitting around dry and corroded is not unusual with carburetors these days. In this video, we will be removing all the parts and preparing for stage two.

We show you how to tackle the job of disassembling the Weber Three Barrel Carburetor.

Taking the Weber Carburetor Apart

We are taking apart a Weber 40 IDTP. There is no difference in the teardown of an IDA, IDS, or IDTP carburetor. A lot of people who do this job get concerned about storing the parts for each carburetor and each barrel of the carburetor. You cannot have a different jet in one carb and not in the other. So it is irrelevant where the jet came from.

We make piles of like items by the material. So all brass goes together, all steel, all-aluminum parts, and a trash pile. These piles will be treated later on and will be processed according to the materials.

Making piles of parts as we remove them from the carburetors
Sort the parts into like materials for later processing

Jumping in and getting the carburetor apart efficiently is our goal. We start on the fuel inlet pipes and cutting the connecting hose is most efficient. Using the right tools for the job will help you not cause any more damage to the carburetor.

TEKTON 1/2 Inch Drive x 16 mm Deep 6-Point Impact Socket | 47807
Klein Tools D248-8 Pliers, Diagonal Cutting Multi-Purpose Pliers with Angled Head, High-Leverage Design, and Short Jaw, 8-Inch
DEWALT Drive Socket Set, SAE/Metric, 1/4-Inch Drive, 25-Piece (DWMT73805)
Mayhew Pro 21232 2mm Metric Pin Punch
Mayhew Pro 21224 4mm Metric Pin Punch
TEKTON 1/2 Inch Drive x 16 mm Deep 6-Point Impact Socket | 47807
Klein Tools D248-8 Pliers, Diagonal Cutting Multi-Purpose Pliers with Angled Head, High-Leverage Design, and Short Jaw, 8-Inch
DEWALT Drive Socket Set, SAE/Metric, 1/4-Inch Drive, 25-Piece (DWMT73805)
Mayhew Pro 21232 2mm Metric Pin Punch
Mayhew Pro 21224 4mm Metric Pin Punch
$14.00
$26.66
$29.99
$12.09
$11.78
TEKTON 1/2 Inch Drive x 16 mm Deep 6-Point Impact Socket | 47807
TEKTON 1/2 Inch Drive x 16 mm Deep 6-Point Impact Socket | 47807
$14.00
Klein Tools D248-8 Pliers, Diagonal Cutting Multi-Purpose Pliers with Angled Head, High-Leverage Design, and Short Jaw, 8-Inch
Klein Tools D248-8 Pliers, Diagonal Cutting Multi-Purpose Pliers with Angled Head, High-Leverage Design, and Short Jaw, 8-Inch
$26.66
DEWALT Drive Socket Set, SAE/Metric, 1/4-Inch Drive, 25-Piece (DWMT73805)
DEWALT Drive Socket Set, SAE/Metric, 1/4-Inch Drive, 25-Piece (DWMT73805)
$29.99
Mayhew Pro 21232 2mm Metric Pin Punch
Mayhew Pro 21232 2mm Metric Pin Punch
$12.09
Mayhew Pro 21224 4mm Metric Pin Punch
Mayhew Pro 21224 4mm Metric Pin Punch
$11.78

Re-Using Parts

A lot of the parts should not be re-used. We do not reuse throttle plates. Throttle plates wear in use, and unless you know their age, it is best to replace them. We will be measuring the throttle shafts after the carburetor is clean. If the throttle shafts measure ok, they can be reused.

Brass gets old and more prone to snapping. The brass parts can be overtightened, you can see the twist on the brass parts. With damage, overtightening, and age, if in doubt, replace the brass part.

Steel parts can be re-plated. Today, with the cost of re-plating parts, it may be more economic to buy new parts. Clean and inspect all parts before any re-plating.

Removing Top Plate Vents

To send a carburetor to be re-coloured, there must be no steel in the body.

The vent tubes are steel. Most likely your vent tubes are already loose and vibrating when you run the engine. This condition will only get worse till they hog out a hole in the top plate.

We remove the vent tubes very simply by bending the peened over edge, till they pop free. Later after the top plate comes back from the color we will show you how to permanently repair the vent tubes.

Removing throttle plates

Removing Throttle Plates and Throttle Shafts

Start with removing the accelerator pump linkages. On aftermarket pump rods there will be a small e-clip. Work on the pump block pin with a 4mm punch before you remove the block from your carburetor body.

Throttle plates from the factory use a peen to lock them in. Using a good quality screwdriver is a must. The plates will be tight and continue to have a tight feeling from the peen. Never re-use throttle plate screws. If you cannot undo them you can use an impact driver. To remove the plates, make sure they stay parallel and slide them out.

There is a 2mm pin in the throttle shaft lever. Use a 2mm punch to remove the pin. Often the lever is rusted in place. And along with the coupling, you need to carefully break them free to remove the throttle shafts.

Removing Auxilliary Boosters and Chokes

With all the brass, steel and throtttle pales removed from your carburetor bodies, you are able to access the boosters and chokes from below.

Being gentle is very important when removing these aluminum cast parts. Using a brass drift, tap ou the auxiliary boosters. You can hear a change in the note when they break free.

Do not use a punch on the bottom edge of the choke. If you cannot just push them out with your thumbs, you can only use a punch that enteres into the choke.

All the parts out of the carburetor. Ready for part two
All the parts out of the carburetor. Ready for part two

Your Weber Carburetor is Ready for Cleaning

Now you have your carburetor bodies clear of all parts you are ready for the biggest part of the re-building job! Cleaning!

You may have noted that we have left the studs in place, this is on purpose because it is easier to blast them in place and then remove them.

We will be visiting our piles in this next episode. The brass, the steel, the aluminum/pot metal, and how we treat then inspect each part.

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4 Responses

  1. I got the performance jet package from partsklassik 901.100.922.02
    I have a 3.0 motor in my 1975 911s
    the webers are 40mm
    the choke that came with the kit are to tall and wont let the pump nozzle mount
    should i cut a slot to let them fit or lower the choke in the carb
    Thanks Glenn

    1. Glenn, There is no way a choke should ever restrict the pump nozzle from fitting. It means that the choke has not been seated all the way down into the carburetor. The carburetor bodies can also be distorted causing the chokes to not seat due to previous mechanics over tightening the choke retaining screw. If this is the case then you may have to address the contact points on the choke to allow it to fit all the way into the carburetor body.

  2. first thanks for the help
    I can slide the chokes down in the carb no problem
    If i do that the locking screws are not going to hit the indent on the chokes
    so just run them flush with the carb and lock them there
    Thanks for the email im installing them this weekend

  3. Thanks for the help
    went back to look at the chokes and this bone head had them upside down
    cant wait to get the kit in and running
    happy new year
    Thanks Glenn

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