SU carb brass float repair

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allan.walker
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SU carb brass float repair

Postby allan.walker » Tue Sep 24, 2019 5:38 pm

I have dismantled the SU carb on my Mk2 for cleaning and inspection and have found that there is petrol inside the float.
I have read advice on how to fix these floats, but before I set about it, has anyone here repaired a leaking brass float successfully?
Would it be better to buy a new one from Burlen?
Thanks!

bob cottam
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Re: SU carb brass float repair

Postby bob cottam » Tue Sep 24, 2019 6:28 pm

The obvious concern is not to attempt a repair to the solder joint with a naked flame!!!

New ones are on the website at £24 or so... still brass- no "Stay-Up" resin type seems to be offered as yet....Bob C

john.whiting
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Re: SU carb brass float repair

Postby john.whiting » Tue Sep 24, 2019 10:35 pm

Fixing carby floats ....first thing you learn mucking about with old cars and trucks.............warm it up with warm water until the bubbles stop,bring it to the boil,use some no-corode flux and solder with an old fashioned "iron",float as good as new.

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Paul_Linden
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Re: SU carb brass float repair

Postby Paul_Linden » Tue Sep 24, 2019 10:35 pm

I get through one float a year for the SU carb on my Square 4, and now find the symptoms easy to spot as it slowly loses its buoyancy. This happens with new ones, second hand ones, and even happened with a “stay up” one. The float bowl is clean and has no sharp edges, so I assume it is the ethanol in petrol.
Curiously, the petrol stays in the brass floats I’ve taken out and doesn’t seep out even after a few years left in a draw.
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

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Paul_Linden
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Re: SU carb brass float repair

Postby Paul_Linden » Tue Sep 24, 2019 10:39 pm

Here is a pic of the stay up float I took out earlier this year. The skin had split and petrol got into the porous inner material. You can see the petrol seeping out.
DA530E10-4FE8-49EB-B524-B14F4B3E9A8C.jpeg
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

john.whiting
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Re: SU carb brass float repair

Postby john.whiting » Wed Sep 25, 2019 5:31 am

The new brass floats Ive had recently seem to have virtually no solder in the seam....I suspect the workers in Mumbai get issued one stick a year,and told to make it last...............anyway,I generally resolder them soon as I get them..............so far the concept of lead free solder doesnt seem to have occurred in India,or China......but then they still use bags of loose fibrous asbestos like it was sand.

allan.walker
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Re: SU carb brass float repair

Postby allan.walker » Wed Sep 25, 2019 8:22 am

Thanks for the replies. It looks like a new float (of whatever material) is unlikely to be a long-term solution, so I may as well try to repair my leaky one.

I'll wait until my wife is out before boiling the float in one of her pans.....

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simon.holyfield
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Re: SU carb brass float repair

Postby simon.holyfield » Wed Sep 25, 2019 2:35 pm

I quite like a hot-air paint stripper gun for repairing those.
cheers

Simes

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allan.walker
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Re: SU carb brass float repair

Postby allan.walker » Wed Sep 25, 2019 4:29 pm

Good idea Simon, although I'll probably need the pan of water so I can see where the leak is from the stream of bubbles.

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Re: SU carb brass float repair

Postby JohnnyBeckett » Wed Sep 25, 2019 5:57 pm

HI Allan try sum sta-bil fuel stabiliser it protects against ethanol and keep fuel fresh i have used it for years keeps all engines good and easy to start and helps stop water in the fuel look it on Ebay


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