SU float bowl vents

[npanne]

Don't know how I didn't already know this - but worth a read : https://sites.google.com/site/.....-carb-floatbowl-info

Pretty fundamental design flaw with the float bowls.

[Nick Jones]

Well, I suppose so, but they aren't meant to leak and usually don't.  At least on a 4 cyl Triumph the electrics are all out of the way on the other side of the engine - and petrol is actually less likely to ignite on a hot manifold than brake fluid.......  I agree that the proper drain appears safer though it may disguise a smaller leak.

On Strombergs it just piddles out into the air filter........

Nick

[nang]

I've actually ran a couple of 1/4" hoses from the vents on my 2500 S. terminating below the manifold. These carbs originally had the emission control junk fitted which I disposed of . This set up caused no end of problems with the vent valve shutting off and causing a vacuum and shutting off motor. Took me a while to realize what was happening.
Tony.

[RobPearce]

Yet more namby pamby pseudo-safety FUD. The existing design, if maintained at all (never mind well) will not leak and even if it does it's going to stink like hell well before there's any actual danger.

Later cars (Dolomite 1500s, certainly) did have a set of hoses to take the float vents down below the manifold level, but this is nothing to do with safety, it's an odour reduction thing.

[npanne]

FWIW, I've just had two such leaks in the space of a week - both caused by crud that an extra filter will catch in the future - but it doesn't take much for the needle valve not to seal, and with an electric pump you do get quite a lot of fuel quite quickly - I'm talking about a constant trickle rather than a drip drip drip type leak.
Yes it smells, and yes it's better to know about it, but I'd rather have it dumping somewhere away from hot exhausts and electrics.