Morris Minor Owners Club

Any carburetor experts out there?
I have an HS2 carb that I’m planning to use on the 1275 engine in our ’61 MM and using stock type manifolds ass’y.
It has a tag w/the number AUD368, a 1 ¼” bore and a needle marked GX.
I’m wondering if this is the correct needle to use in this carb for this engine?
I see Bull M list a “AN” needle for a 1098 engine and suspect that might be a better choice?
We’re not looking for high performance, just good running and hopefully good gas mileage.

Hmm - it's far too small for a 1275 engine! It will run - but will grossly limit the power produced - but may be good for mpg I suppose. Just try the GX and see how it goes - spark plug colour is the guide.

Katy
The AUD368 carb was listed for an Austin 7 cwt Van 1098cc 1972/73
and Austin 1100 ( 1098cc) 1971/74
Needles Rich H6 Std AN and weak EB...i.e the same needle range for a Morris Minor 1098cc and all with a Red piston spring.
The GX needle was listed as a Standard needle for a Morris Oxford 1622cc 1961/71. ( Not noted for a lighting turn of speed !! )

For example.. the AN needles were listed as Standard for 1275cc Sprites 1964/1971 (but Blue piston springs ).
From the car's history, do you know where the 1275cc engine was sourced ? This would help identify the original set up.
A thought...if you are ordering a gasket set/ service kit or a full overhaul kit, ordering a new needle and/ or spring at the same time might save a little on postage ?

Bob

Bob

Try this link katy.. it may help, it may not.. At least it will tell you what bits are for your carb.

http://www.sucarb.co.uk/ExplodedImageCl ... ctId=10922


Or you could look for the right carb for your engine. I would suggest anything Austin with 1300 engine... such as the wonderful 1977 Austin Allegro 1300
http://www.sucarb.co.uk/ProductSearch.aspx

What about this one???

http://www.sucarb.co.uk/CarbList.aspx?p ... =&Id=10759

Maybe a telephone call to them would solve all your problems??

moqbob,
I have no way of tracing the actual history of this engine. The engine S/N is 12V 671Z Lxxxx, which I have been told is from a Sprite Mk4 or MG Midget Mk3, 1973 era

When we got the car it had dual carbs, one worked fine but I could not get the other one leaned out enough to get it to run properly. Also, the exhaust manifold was broken and the exhaust system was all patched together and cobbled up. I was able to source a set of what I believe are stock manifolds and the HS2 carb.
The manifolds are similar to the ones shown on page AA.6 of the workshop manual.
So rather than having the broken (w/pieces missing) exhaust manifold repaired and going to a muffler shop to have a custom exhaust system made I plan on going with this setup and a stock exhaust system.

You mentioned a red piston spring. I looked at the spring but could not see any colour on it. Should the colour be obvious? Or does one have to look in a specific place?

Don't worry about spring colour! It hardly matters. Just try the needle you have - GX - and see how it runs. there has never been a 1275 standard engine with single 1.25" carb - so there is no obvious precedent. It will run with that needle - if the plugs are white then a richer nedle will be required, and if they are black - then a weaker needle will be needed. But until you run it - there really is no way of knowing.

A usefull website is http://www.mintylamb.co.uk/suneedle. This site enables you to compare different carb needles by drawing graphs of their profiles. Therefore if you find that the GX is too weak then you can enter it on the chart and choose another needle, eg AN and see how it compares.
If you can find an HS4 or HIF 38 carb then they would be more suited to the 1275 engine, however each one has different mountings and would need the correct manifold. Also the HS4 manifold looks like the HS2 manifold but is a larger bore and does not fit the standard 1098 exhaust pipe.

Katy
There should be the remnants of some paint on one of the ends.Old age/ previous owners over entusiastic cleaning, etc might mean that there is nothing left to see.
I agree with Roy/bmcosse don't worry too much about the spring colour.
Go with the set up you have put together and see how it goes.

Bob

Thanks for the replies and the links, much appreciated.
Ken