Yes a LH float bowl will fit on a RH carb and vise versa.

Maybe it is a porous casting?

And it is leaking again. going to try the tighten the hell out of it. I agree there is something wrong. the right hand carb does not leak never did. of course this is the float bowl that is interfrring with the master brake cylinder. I broke the first bowl that was on it and replaced with a bowl from a different SU carb. 
I believe it is OK to put a right hand float on the left hand carb. it fits fine.

I don't really want to go back to a single carb.

not to rain on your parade but you should not need any sealant. There were millions of these in use and other than botch jobs all i have seen are just the way they came from the factory, something else must be amiss.

OK I did get it to stop leaking. I played with the old one and measured how far in the tube could go. got a feel for when the nut was going to start compressing and so on.
then I put seal-all on the tube and rubber seal and behind the rubber seal and then turned the nut in until I could just barely tell it was compressing and then pulled the spring back and made sure the tube was still in far enough and filled the back of the nut with seal-all and left it sit face down for 5 hours until it dried. I then turned the carb up the right way and filled the bowl with fuel and left it sitting overnight in the garage. not a drop leaked out. I reinstalled and pressurized the system. the peeing sound is simply the sound of the fuel filling the float bowl with fuel not a leak. I then left it sit for about an hour and no fuel leaked out! 
If I tried to "tighten the hell" out of it then it just pushes the seal off the end. making sure the tube was in place and not trying to pull it in with the nut was the best way to do it. the seal-all is just insurance so that I don't have to spend another 30 bucks on a new Jet tube.

and BC all I can say is:
"I never understood a single word he said
But I helped him a-drink his wine
And he always had some mighty fine wine"

the twins at the trailer park.. still love me . they have just got them a new SKINNY ( redneck slang for single wide trailer.) both off parole now. and still have lovely 38 DD. big butts stunning blue eyes .raven hair.. great smiles.. and like to drink red stripes in the morning.. what more could an old man like me wish for in life?? later b c

It seems like you are not tightening it up enough. Practice on the old one you should not be able to pull it out of the float bowl without damaging the jet tube.

Ian/minibitz

My apologies, dummy me, NZ, OZ of course, always had trouble with those flags

Big AL

Have you tried tightening the brass nut with more pressure than just "the weight of the wrench"? If not, tighten the hell out of it after you are certain that the tube is fully inserted through the washer and into the bowl, and that everything (o-ring, ferrule and washer) are correctly positioned and seated.

Well we do like helping .... Canadians as much as  anyone.

But Minibitz may not be too keen on being misrepresented....

Cheers, Ian

I have  not run into this problem with a carb but with any similar compression fitting I make sure the tube is fully seated in its hole before starting the threads of the nut that does the squeezing. Sometimes it is necessary to measure the depth to ensure it is fully inserted. Don't rely on the threaded parts to pull it in - they should thread easily by hand almost all the way with some torque to do the actual compressing.

Yes the O ring was on the feed pipe first. just as it came out of package. 
yes the inlet on the float bowl is clean.
I just can't tell when it is tight. there is no feed back like any kind of pressure on the "nut" where it is beginning to compress the O ring

it just slips off the end of tube. 
It is almost like the brass insert that is in the straw is not large enough or the "washer" is too large and has no resistance.

the design leaves much to be desired. I think the brass insert in the end of the pipe should be tapered so the "washer" can't come off then it would be so easy to tell when there is a bit of pressure and the seal has made contact.

Oh well I guess I will go back to the single. I can't afford 30 bucks every ten seconds and 2 weeks for another one to arrive in the mail. there must be a better way or some "trick" to stop it from leaking

 

Love it, Australians helping out Canadians

Get used to it, this is what the future is going to look like

Tarrifs not withstanding 

Big AL

You need to have the O ring on the jet feed pipe, then push the tube into the float bowl and tighten the nut. This then compresses the seal making it a tight fit on the tube and body of float bowl.

Sounds like you are you putting the seal into the lost bowl then trying to push the tube in? 

The O ring seals are a one time deal so if you stuff it up get another and try again. Also make sure you have dug out all of the old seal first.

OK so still having issues with the twins on my car. long story but let me try and recap.
set of HS4 carbs on what we believe is a mk3 intake (from post last summer)

Intake is making contact with header mount points. this has been solved as of yesterday I simply filled a bunch of stuff off the intake and it fits now. 

also last year the left carb float bowl was making contact with Master brake cylinder. I filed some of master cylinder and also filed the locating tab off the float bowl so that it would swing further away from firewall. or stand straighter.

Now up to the continuing problem. The Jet tube leaks. on this carb it has leaked a bit since I put them in. last year I just coated it with seal-all and it contained it enough that I could drive.
so today I decided to replace the J-tube. I very carefully get the tube attached to carb first on the needle side then into the float chamber. I tighten it by hand to where I figure it has made contact with the rubber gasket. I install to car. I turn on fuel pump and can hear the peeing sound of fuel being sprayed all over. can't see any but the tube is wet/weeping I wipe it off and tighten with my fingers a bit more. repeat, same sound more weeping. I take wrench and using no more pressure then about the weight of the wrench I tighten a bit more. pressurize system and fuel is dumping out of tube.

this is the 3rd one of these little tubes now. I can keep throwing 30 bucks out all the time. I have tried and can not seem to put the little washer and rubber gasket back on and have it be leak free.

what am I doing wrong