Weber 2V carburettor - adjustment
Idle speed/mixture
1 Refer to Chapter 1, Sections 10 and 11 according to model.
Fast idle
2 Open the bonnet and remove the air cleaner.
3 Run the engine until the normal running temperature is reached. Hold the throttle partly open, then close the choke plates by hand and release the throttle.
Choke pull-down/fast idle setting - Weber 2V carburettor
A Hold choke plate shut B Hold throttle partly open
4 The throttle mechanism will hold the choke mechanism at the fast idle position. Release the choke plates, which should return to the open position.
5 If the choke plates do not fully open, then either the engine has not fully warmed up, or the electric choke is faulty.
6 Without touching the throttle, start the engine and check the fast idle speed against the figure given in the Specifications.
7 To adjust the fast idle speed, slacken the locknut and screw the adjuster
Fast idle adjustment showing choke plates open (A) and fast idle adjustment
screw (B) - Weber 2V carburettor
in or out as required.
8 Tighten the locknut and refit the air cleaner.
Vacuum pull-down
9 With the air cleaner removed, pull the wire off the electric choke.
10 Remove the three retaining screws and lift off the automatic choke outer housing with the bi-metallic spring. Lift off the internal heat shield.
11 Fit an elastic band to the choke plate lever, and position it to hold the choke plates closed.
Hold choke open with a rubber band (B) and push the diaphragm rod (A) with a
small screwdriver (C) - Weber 2V carburettor
Open the throttle to allow the choke plates to close fully.
12 Using a suitable screwdriver, push the choke diaphragm open, then measure the clearance between the choke plate and the carburettor body, using a gauge rod or twist drill of the specified size.
Insert a twist drill (A) and adjust pull-down (B) - Weber 2V carburettor
13 To adjust the opening, remove the plug and screw the adjusting screw in or out as required.
14 Adjust the choke phasing, as shown below.
15 Refit the heat shield and the choke housing. Reconnect the electric choke wire and the air cleaner.
Choke phasing
16 Adjust the vacuum pull-down as shown above.
17 Hold the throttle partly open, and position the fast idle adjusting screw on the centre step of the fast idle cam. Release the throttle to hold the cam in this position.
18 Push the choke plates down until the cam jams against the fast idle screw.
Checking the choke phasing - Weber 2V carburettor
A Fast idle cam
B Fast idle adjuster screw
19 Measure the clearance between the choke plate and the carburettor body, using a gauge rod or twist drill of the specified size.
20 Bend the tag
Choke phase adjusting tag arrowed) - Weber 2V carburettor
as required, to give the correct clearance. 21 Refit the heat shield and the choke housing. Reconnect the electric choke wire and the air cleaner.