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Float Chamber for SU carb

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Float Chamber for SU carb
#1
  This topic is about my 1973 MG Midget MkIII
The Red Baron Kris !
Anycity, Anystate, USA   USA
Hello:

My front float chamber on the 1973 MG (SU carburetor) has come loose. Also, the small fuel tube from the bottom of the chamber has come loose and the fuel is flowing out. I have not seen the information on how the float chamber connects to the carb. Rear one is tight and looks great.
She has been stalling at lights occasionally and coughing a bit too. Probably needs a carb clean I would imagine. Where can I get info on reattaching these? I have seen where some people have put new style carbs on for better performance but I want to keep it as is. It would appear to be an easy fix but I could use some advice.



Thanks.

Kris

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AN5L8016 Avatar
AN5L8016 Mark Haynes
Nederland, Colorado, USA   USA
The Float bowl is held on by a crossbolt from the carb body( Item 28 in the photo), the bolt threads into the float bowl. Each float bowl has an elastomeric insert that keeps the bowl level, be sure to retain this and reinsert it in the correct orientation.
The small gas line is part of your jet assembly, its held into the float bowl with o-rings and washers compressed by a nut. Usually a leak here is the sign of either an improperly assembled jet tube or a broken feed line. Your best bet, since the float bowl is loose, is to disconnect the choke linkage from the jet, pull the cover off of the float bowl, remove the bolt holding the float bowl and pull the bowl and jet together, then see if the leak is the feed line or the assembly of it.
Curto HS exploded



'58 Bugeye
'05 Mini Cooper S

S1 Elan Kurt. Appley
Akron, Ia., USA   USA
A Weber carb is definitely not a performance upgrade but just the opposite.

Kurt.

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The Red Baron Kris !
Anycity, Anystate, USA   USA
Thanks for responding about crossbolt on float bowl. Have it all tightened up. Only problem is that I am leaking fuel from the jet connection at the bottom of the float bowl. I was unable to find a wrench that fit the nut. Used both SAE and metric. I have the jet in as far as it can go and the nut snug with a needle nose plier. I could not really get it as far as it can be tightened. Am I missing something? What fits this nut? I heard of a John Whitmore wrench. Car starts and runs but fuel leaking.

66jalopy Avatar
66jalopy Silver Member Phillip Jolliffe
Lake City, FL, USA   USA
Because of float being loose you may have damaged the flexible hose. I would replace the jet assembly. Interesting, I never had a problem with the nut size. I checked a spare bowl I have. A quality 7/16 wrench won't fit, it is 3/16 Witworth. I have been using this cheap Sears one for decades, it is tight but will work, the Craftsmen adjustable will of course work. An 11mm that many use instead of a 7/16 is definetly not an option. Take an old 7/16 and grind a little out of it.



Edited 1 time(s). Last edit at 2017-06-17 05:00 PM by 66jalopy.


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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Not uncommon for that little plastic hose to crack when it gets old if it is flexed too much. Agree with Phil, you may have to replace it.

Kurt.

ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
Replace the hose with a new jet kit as Kurt mentions. If it's leaking it's prob shot!



Iceman

Atlanta GA

60 AH MK1
62 AH MKII
67 Midget
71 Midget

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AN5L8016 Avatar
AN5L8016 Mark Haynes
Nederland, Colorado, USA   USA
when you buy a jet tube assembly, be sure to get it for the correct carb, front or rear, as well as the model -HS2 or HS4. the feed lines on the jet tubes are pre-bent and the holes for the choke attachment are open on differing sides.



'58 Bugeye
'05 Mini Cooper S

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