MG Midget Forum

float bowl overflow

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ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
doug, surprised to see the two different float bowls. Can't make the engine run well with that situation ongoing.


Atlanta GA

60 AH MK1
67 Midget
71 Midget

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Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
the hole in the brass part of the jet is supposed to be 0.090", for an HS2 carburetor

If your second photo (kind of blurry) is showing that one is not that diameter then the wrong part was sent to you and must be replaced by the vendor with the right one. There should be colored bands around the tube denoting "part number" (Burlen's SU catalog includes a list of them so you can look it up if you want to). If the correctly colored bands are on the one without a .090 hole then the mistake would go all of the way back to them.

Regarding the shape difference of where the jet tube attaches, at the bottom of the two float bowls, it simply looks like a shape change to save cost: the upper one required a drilling operation, the lower one was able to be cast without additional machining. The purpose of that little shape is to prevent hard cornering from making the fuel surge when it is sucked up into the jet, so the shape of it shouldn't matter for that purpose.

I am guessing the bottom one is the later year and as you noted, the part number was mostly the same but with an additional number below it, probably to indicate a change was made to the shape for cost reduction (a big push for cost reduction followed the Leyland take over in '68). What was the number below the "AUG 1310"?

Someone like Joe Curto could say with certainty about the bowl differences.


Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
oops, I almost forgot to add: look closely at the shape in the side of the float bowl, it is cast in line with the overall shape of the bowl, this means that the angle of it, when attached to the rest of the carburetor is completely controlled by the rubber grommet

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Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
I just looked it up:

HS jets for all Spridgets from '58~'74 (0.090"winking smiley:

AUD9141 RH connection Black/Green
AUD9142 LH connection Black/Pink

"RH/LH" refers to when looking down from above, with the engine flange away from you and the intake towards you (standing on the LH side of the car looking down on the carbs). So, I think '41 is rear and '42 is front.

AUC1310 is the correct float bowl part number for angled uses (like the Midget), which also use a rubber angled adaptor.

The angled adaptors that are orange/brick in color (like in your photos) are wrong for a Midget, they are 30degrees, meant for a mini. The Midget uses 20degrees, and those are colored red, green, black or grey (I can't figure out from the catalog which is which, but that's ok, it is enough for now to clarify that when you get the new ones they will be a different shape from the ones you currently have. As the others have pointed out, the key thing is that your float bowls must be vertical when installed.


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Speedracer Platinum AdvertiserAdvertiser Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Yep some Midgets has float bowl lids where there was no brass overflow/vent tube, just a vent hole, one of the above float lid is that type. They from the factory has a aluminum dust/debris shield over the hole. Here's one with the shield in place,and one without the shield.

with shield:

with shield removed:

Hap Waldrop
Acme Speed Shop

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littlecars Avatar
littlecars David Bassett
Nashville, TN, USA   USA
1965 Chevrolet Corvair "Ski Team Transport SOLD!"
1965 MG Midget MkII "Buffoon"
1966 MG Midget MkII "Swiss Cheese...SCRAPPED"
1970 Triumph Spitfire MkIII "Tamara's Turd... SOLD!!!"    & more
I can't believe I got my 1965 running, and idling pretty well last summer. DPO had one of the weep holes plugged with what looks like a toothpick, and the other open, with the correct aluminum cap as shown in the two photos from Hap.

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
yes my float bowl adapters are wrong.
so i close my eyes and hope Moss sends the proper ones...since ordering, I have found this from SU (pic of adaptors and part numbers)

as for the bowls themselves- AUC 1310...but they are different inside, there is another number beneath the model nu8mber- front bowl P.D.C.I. (has round fuel out in bottom) and the other PDC6 (has square fuel out port).
not sure if there is any harm there, but picked up a matched pair on ebay for $20 anyway.

as for the jet openings- they are both in fact .090 , but looking closely, the one that appears larger has a beveled edge, when the other does not....again unsure of significance.
Moss however sells the jets as specifically front and rear, stating the rear has a longer spring covered fuel line than the front. I dont see why. at least in my setup there is no difference in distance to the carb between front and rear. Those jets were in fact purchased from Moss as a front/rear pair...not sure why the machining would be different...AND the fuel line lengths are the same.

if Moss were to fail me again on the proper adapters- does anyone have a source for SU parts by mfg part number here in the states?

float chamber adaptors.jpg    53.3 KB
float chamber adaptors.jpg

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dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
another brief point..
as Larry mentioned a few pages ago on this thread, the rubber may look good from the outside, but inside have turned to goo.
such is the case on both carbs on the head side of the bolt that secures the float bowl thru the carb body - a rubber shouldered washer...pretty much deteriorated to nothing.
that is what was causing my swing movement.
Thanks to all for your help- I'm going to fix what we have diagnosed thus far and see if my leak is gone...then on to the next issue...last time round the block there was an odd popping noise from the front right suspension/steering....bloody disconcerting.....
but that will wait for another day.

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