4.4 - Flooding SU Carburetors ( Alastair Reynolds,  )

Have you ever had a flooding carburetors, worse still have you completely replaced
the float needles and adjusted the Float Chamber Fuel Level and still had intermittently
flooding carburetors. If the answer is yes then read on.



Float Chamber Fuel Level Adjust
The jaguar manual probably reads something like the following:
When the fuel level setting is correct a 7/16" (1 1. 1 mm.) test bar will just slide between the
lid face and the inside curve of the float lever fork when the needle valve is in the " shut-off"
position (Fig. 9). If the float lever fails to conform with this check figure, it must be carefully bent at the
start of the fork section to correct. Ensure that, both forks are level and that the straight portion of the lever is
perfectly flat.

Not Enough
You think this is all you have to do, wrong! You can have perfectly adjusted carburetors
as per the book and still experience intermittent flooding. The cause I found is another
adjustment that is not shown in the any of the books. Have a look at the following
photographs to illustrate what I mean.





This photograph was taken with the top of the carburetors on it's side, after following the
above recommended procedures.







This photograph was taken prodding the fork upwards with very little force!







The real part of the story is told here! Look how you can twist, without any
significant force, the fork to make an angular attitude. This is what causes
your flooding problem in my opinion. The float is not a perfectly balanced item
and this badly adjusted fork can effectively raise the fuel level in the float chamber
enough to cause intermittent flooding. The fuel level can also be affected by uphill
or downhill attitudes of the car in the presence of this badly adjusted fork.








The cure is to take a small pair of pointed pliers and adjust the hinge end of the fork to remove any
lateral movement in the hinged fork. Simple really! Both myself and Alastair Lauener have had this
problem on our 60's S Types!