MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - su carbs overflowing

lve just lately bought a 78 1500 midget only problem is the front su carb keeps overflowing. lve changed the float needles and seats but still the same been told this is a common problem just hoping someone can help
c smith

Has it been converted to use an electric fuel pump?
Trevor Jessie

no its still mechnical
c smith

Is the float bowl loose on the carb (allowing the angle to change)?

Are you sure the float doesn't have a pinhole leak?
Trevor Jessie

And... any crud in the float bowl?
Trevor Jessie

no the floats fine and the bowls tight and clean forgot to say l have a spare set of carbs and when l tried these the problem was still there
c smith

Can only leak for 2 reasons. Float not sealing on needle valve or angle of the float bowl is wrong making it impossible for the float to seal. The 2nd is a common propblem where the seemingly indentical carbs have been swapped from one model of car to another without appreciating the difference in angles. Part Numbers
AUD2178 ADAPTOR, float chamber, front
1500cc (1975-1979)
AUD2179 ADAPTOR, float chamber, rear
1500cc (1975-1979)

Perhaps they got swapped around or damaged?
P J Guest

Fuel inlet pipe connected to the overflow pipe by mistake (does the 1500 carbs have an overflow pipe)?
Gary lazarus

Hey gary,

You should ask Treavor if he has any experiance with your suggestion. LOL.

I will never forget that image at spridget 50, treavor is covered in fuel, fuel everywhere, you cant breath more then 5 minutes without getting high off the fumes...all inside the hotal brease way, and I look over had theres Frank claricy lighting up a smoke not more the 10 feet from treavor, frank was so laid back like "What ever man---Im on break" just leaning agianst the piller leg proped up, how the brease way didnt detonate into a hugh fire ball is beyound me, but i think about the moment fairly often and just laugh...it was just a classic moment...But Im pretty sure treavor didnt find the humor as well as I did, I only lagh NOW because the situation was rather un-eventfull.

Prop

Sorry forgot to mention... could there be an issue with the intake manifold

On the 1275s I know you cant use a mini cooper intake manifold on a midget as it to will do lik you described...

by the way did you measure the float gap, on the HS4 carb the floats are adjustable...unlike the HS2s that are fixed


But Id sayy the main issue is ...Its a triumph...LOL sorry. Hahaha
Prop

thanks for the help but after cleaning the fuel pump filter which was full of crap all is well now. dont know why this would do it any ideas without the triumph jokes lol
c smith

if the fuel pump is loaded with trash... Id say it could have been transfering junk thur the fuel system and effecting the new seatings

SU carbs LOVE to be clean to work properly

A few ideas... always keep your gas tank a minume 1/2 fuel, and do 2 clear filters before the carbs a big one then a small one, that will help....once you have some down time, drop the tank and have it cleaned and re-sealed or there are kits that you can do it yourself....thats the real cure.

I used to belive a filter before the SU pump, but after talking to David Debuis, Im a convert to NOT doing that.

Prop
Prop

Prop - "...but after talking to David Debuis..."

I believe that is DuBois ;-) Cheers - Dave
David DuBois

Heck David,

I did manage to get the (D,u,b,i,and an S) in there....5 out of 6 aint half bad in my book....LOL

Sorry about that, Ill try harder for perfection next time.

BTW... Can I get a shameful and completely for profit capitalist PLUG from you? I lost your website address somewhere in my computer, And it still has not turned up in some obscure folder

Prop
Prop

This thread was discussed between 21/08/2010 and 25/08/2010

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.