Big Healey S.U. Carburetor & Fuel System Details


Tech Data for 100/6 & 3000, Mk 1 – 2- 3

(information from AUSTIN-HEALEY: OWNERS WORKSHOP MANUAL, by Kenneth Ball, Autopress Ltd. 1973)

Dimensions are in inches unless otherwise stated

“A” refers to the 2639 cc engine with 2 port head
“B” refers to the 2912 cc engine 
“C” refers to the 2639 cc engine with 6 port head

While I have tried to be accurate as possible, it is very likely that there are typos and errors on this page.  Please note that no one associated with assumes any liability arising from the information presented here.  If you find a mistake, please let me know from the contact page and I will correct it.


Fuel system:    
               A   SU electric type HP
               B Mks II and III SU electric type LCS
               Later MkIII SU type AUF 300
     Tank capacity:    
               A and B   12 gallons (54.5 litres)
     Fuel pipe outside diameter:    
               A, B and C   .375 (9.52 mm)
     Maximum flow per hour:    
               B   15 gallons (68.25 litres)
               C   12 1/2 gallons (56 litres)
     Suction head:    
               B   18 (457 mm)
               C   33 (810 mm)
     Delivery head:    
               B and C   48 (1219 mm)
     Cut off pressure:    
               B and C   3.8 lb/sq in (27 kg/sq cm)
Carburetor types:    
     A   Twin SU horizontal H4
     B and C   Twin SU semi-downdraught HD6
     Mark II   Triple SU HS4
     Mark II (series BJ7)   Twin SU HS6
     Mark III   Twin SU HD8
     Needle (normal):    
     A   AJ
     B and C   CV
     Mkll   DJ
     Needle (normal):    
               Mk II (series BJ7)   BC
               Mark III   UH
     Needle (rich):    
               Mark II   DK
               Mk II (series BJ7)   RD
               MkIII   UN
     Needle (weak);    
               B   DH
               Mark II (series BJ7)   TZ
               MkIII   UL
     Jet size:    
               A and B Mks I and II .090 (2.29 mm)
               Mk II (series BJ7) .100 (2.54 mm)
               MkIII .125 (3.18 mm)
     Spring colour code:    
               B  Mk II Red
               MkIII Red and green
               C   Yellow
     Float setting:    
               MkIII   .125 (3.17 mm)
               Mk II (series BJ7)   1.75 (44.45 mm)
               MkIII   2 (50.80 mm)
     Air cleaners:    
               A   Twin ‘pancake’ type
               B   Oil wetted

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