carb fuel leak

[dalgrae]

I noticed yesterday a small petrol leak that appears to be coming from the carb jet location where the flexible pipe joins to the brass tube that slides up into the bottom of the carb jet block on my AUD13 type carb, all the books I have just show this item as being a sliding fit into the jet block/mixture adjust nut with no apparent seal at all .I took it all apart and this was confirmed and as everything looked OK so it was all put back together, how is this item sealed or is there always a slight witness of petrol at this joint

[MarkyB]

Check that the float is at the right height.

[dalgrae]

Thanks all the settings are fine, my concern is that this brass tube is just a sliding fit within the jet block with no apparent seal at all , may be during running and under vacuum conditions it cannot leak but as soon as the engine is switched off any residual fuel can leak down this tube , it must be able to move as it does so when the choke is pulled out as the bottom of the tube is connected to a link on the choke mechanism , so may be it is acceptable to show sings of a leak and will so evaporate away , it is just a bit disconcerting

[bmcecosse]

There is a small rubber O ring seal in there........

[dalgrae]

Thanks BMC can you please point me to a diagram of this as I cannot see it on the Moss parts book or my other manual , the only seal shown within the parts book is a small brass/copper washer which is external of this sliding tube

[mogbob]

http://www.sucarb.co.uk shows a full colour parts breakdown of an AUD 13 carb.
It's probably a phone call to the Company ( satisfied customer, no connection )
for the rubber seal, not listed separately.
Bob

[dalgrae]

Thanks for the advice I will phone SU

[bmcecosse]

Thinking about it - I'm not sure it is an 'O' ring - more a little square section ring - but definitely a rubber seal of some form in there.

[dalgrae]

I have not got to the bottom of this yet but after looking at the S U website the best guess I can come up with is that there is a captive rubber seal in the jet block where it meets the mixture adjusting nut , I have not found any picture that actually shows any other seal at all , I can only assume that when running the seal is pressed up tight enough to the adjusting nut to effect a good enough seal to stop any fuel leaking ,but this is only a theory at the moment until I remove the jet block again , if it is worn this will then present me with another problem as the choke link is attached to the bottom plastic fitting with a screw , this type of jet block is not available from S U so it will mean the later jet block and the corresponding choke mechanism will have to be bought and fitted