4.2 S1 Middle Carb Leak.

[eTypeG]

The middle carb on my S1 4.2 leaks from the underneath when on choke, but is fine when not on choke. Anyone any ideas why?.

[JagWaugh]

Almost certainly a cracked jet diaphram. Do all 3 carbs.

Andrew

[christopher storey]

Or it could just be that the screws holding the jet assembly to the carb are loose. These are the 4 screws at the very bottom

[abowie]

Christopher might well be right, as the choke bracket is attached to two of the 4 screws that hold the base of the middle carb.

The screws are slotted; you should be able to access them by removing the airbox.

[eTypeG]

Many thanks for the replys, I will try the screws first. Can the jet/jet diaphram be sorted in situ or will all the manifold and carbs have to be removed?.

[christopher storey]

As far as i can recall, the jets can be changed with the carbs in situ, but it is a rather fiddly job getting the jet holders off ( disconnecting and reconnecting the choke lever connections is a particular swine ) and back on again mainly because you can't really see what you are doing. Also particularly with the rear carb there is limited clearance between the carb and the frame tubes etc

[Moeregaard]

As Andrew says, remove everything and replace the jets in all three carbs. It's a perfect opportunity to clean everything up and you won't be driving around wondering when (not if) the next carb will start leaking--or when you'll experience a fire.

[abowie]

It's a lot easier to deal with the diaphragm with the carb off the car.

You can get the centre carby off relatively easily (well, it's possible, not easy). If you intend to do all 3 carbs and you have a RHD car, take my advice and remove the inlet manifold from the engine with all 3 carbs attached. A couple of the studs holding the carbs to the manifold are pretty much inaccessible. See http://www.projectetype.com/index.php/t ... ck-on.html