leaking carburettor

[bootlid]

bmcecosse,your diagram shows yet another setup, with three fibre washers in all and no aluminium washer or rubber grommits,have not examined surfaces of aluminium body etc,will do soon.

[bootlid]

petrol seems to leak out after engine has stopped,not sure about pump type,12volt s.u.

[bmcecosse]

But is it leaking from the float bowl mount - or the jet assembly seals?

[bootlid]

leak coming out of top fibre washer where bowl joins carb body

[bmcecosse]

Either the washer isn't clamped enough - or it's damaged - or the body is cracked - or the bowl stem is cracked. There must be a reason.

[bootlid]

tried another bowl and new fibre washers,still leaks but not when car is being driven,seems to leak if you turn on ignition a few times .[frame][/frame]

[bmcecosse]

Neat under-bonnet..... Your battery clamp is perilously close to the terminal connectors - I would turn the battery round asap - but do preserve the polarity. Leaking as you describe suggests the float valve is passing. When the engine is running, it uses up the fuel so the little bit of fuel coming through is used up.

[bootlid]

take your point about battery,also been suggested by others about float lid,would like to try new float lid assembly but burlem want £48 for a new one ,noticed morris 10/4,morris 8 ones cheaper,are lids not the same.[frame][/frame]

[bmcecosse]

I can't remember on these older carbs - but surely you can just change the valve ? meantime - I would try setting the level down a bit to see if that helps. Car looks v smart!

[bootlid]

I,ll try and set fork on lid if i can find proper bar,thanks for your comments about car,waiting on replacement sump from mmoc as mine is leaking been welded and smothered in fibre glass,always something needing done,looking forward to "diesel day" at bo,ness in october,hope railcar is running,ive waited ages for my new bachmann derby light weight unit ,goodness knows when delivery will come.[frame][/frame]

[bmcecosse]

Hah - I doubt you will see me at 'Diesel Day' - although I am a diesel driver.... The DMU has been out and about recently.

[bootlid]

carburettor still leaking badly,it is coming from the jet area,leaking down to the adjusting nut and making a right mess ,i have reset float bowl to a lower level but made no differance.

[bmcecosse]

Can you tighten the jet gland any?

[bootlid]

is that the large nut above the adjusting brass nut,i have never stripped this carb.but someone else got the job of fitting new seals and gaskets but still the leak persists.

[bmcecosse]

Yes - it should be nipped up - but make sure the piston still rises/falls freely.

[bootlid]

I am sure i tried tightening up this nut but then i found the choke would not pull out,i,ll have another go on monday.

[bootlid]

Tightened large nut ok,piston appears to operate normally and choke,but petrol still leaking out at thick large washer above the large nut in question.

[bmcecosse]

Either there is a washer/seal missing - or damaged surfaces - or it need further tightening........

[bootlid]

will investigate further.

[MarkyB]

"Nipped up" sounded about right to me, it's going to be a bigger spanner than brass into aluminum will be able to withstand.

I had a dual choke carb once that had gone porous, not something I've ever heard of on an SU but every night the float chamber would be empty.
How ever there was never a visible leak. Maybe if I had been able to afford to keep running it there would have been?