RUNNING ADJUSTMENTS
TWIN S.U. CARBURETTORS (Type H6)
Tuning
Multi-carburettor installations cannot be successfully tuned unless the
general engine conditions (such items as tappet clearance compressions) and the
ignition system are in a satisfactory state.
With regard to the carburettors
themselves the cleanliness of the suction piston units, the position of the
needles, the jet centring and oil level in dampers, etc., should be checked.
With the aforementioned in a satisfactory state, refer to Fig. 27 and proceed as
follows :-
1.
Remove air cleaners from carburettors.
2.
Slacken clamping bolt on throttle connecting rod (4) so that throttles may
be set independently.
Ensure that the throttle adjusting screws (3) are
holding the throttles open and that the jet adjusting nuts are not screwed
right up.
Disconnect the mixture control rod (5).
3.
Ensure that the screw (2) is clear of its abutment and that the choke
cable is not likely to hamper jet adjustment. If necessary, disconnect
choke cable.
4.
With the engine at normal running temperature and the idling speed
approximately 500 r.p.m., check the hiss of air at carburettor intakes
with a piece of tubing approx. ⅜" (9.5 mm.) bore.
Fig. 27.
Carburettors.
1.
Air cleaners.
3.
Throttle adjusting screws.
2.
Choke control screw.
4.
Throttle connecting rod.
5.
Mixture control rod.
3 3
SPORTS CAR