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Carb airflow balancing

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I know that a lot of advice has been given on this topic but I would like to add some new thoughts to give a simple tune up procedure.

1 set timing to 20 degrees advanced, I do this with a strobe which will work at cranking speed.

2 check that the carbs are filling and not flooding, if not deal with the float chambers.

3 set the butterflys to open together, I have come up with this idea, use a length of feeler strip or even a piece of thin plastic strip. Push this under the butterfly on one of the rear venturies and adjust the engine speed screw on the lever of the rear carb until the strip can be felt dragging as you pull it out, by carefully adjusting the screw you can get a nice 'feel' as the strip is pulled out. Test both the rear carb butterflys, if there is a variance you need to sort the problem. Now use the carb balance screw on the front carb to achieve the same feel as on the rear. Go back to the rears to be sure all butterflys are the same.

4 take out each slow running adjuster and clean it, removing any burrs etc, put it back and gently screw it home and back it out 2 turns

5 open the throttle adjuster screw by 3 turns

6 start the car and warm up the engine

7 do the hiss test with a pipe in each Venturi or use a manometer or balancing meter and adjust the mixture screws for balance and good running

8 set the mixture using your best methods Colourtune or other, I use a Co meter in the exhaust pipe.

good luck

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