HS2 Carburettor rebuild - Float issue

[blue_cortina]

So I'm trying to do an HS2 carb rebuild on my son's 1970 Minor. I've just fitted a new valve from a CRK104 rebuild kit and a new "Late HS2 - StayUp" float. The float has no moment and it seems all wrong, hard to explain... The old and new valve assemblies seem a similar size. The float seems jammed between a tag at the back and the pin of the valve - it just doesn't move up and down how I'd expect.

Anybody got any ideas as to what is going on here ?

[philthehill]

The new float is not the right one for the float chamber lid - therefore I would suggest that you fit the float and valve lever as found in the float chamber.
If the original type float is not punctured (and that can be checked by placing the float in warm water and if there are no bubbles exiting the float it is ok) you will have a much better float in the carb.
There should be a tag on the top of the float chamber which gives the type of carb fitted. Not all HS2 carbs are the same.
This is the parts list for the AUD13 tag carb which is the HS2 carb for your Minor

http://sucarb.co.uk/carbspec/carburetto ... s/id/1907/

[kevin s]

It looks to me like you have the wrong carb or float chamber lid for a 1970 car , our 1970 car had /still has the plastic float, they are I believe the original parts. (Certainly been there 20 years).

I have probably got a spare lid somewhere if you need it, not sure if there are other differences with the earlier carbs though.

One thing I did find is the aftermarket fuel pump kept overwhelming the float / needle valve, I ended up fitting a filter king pressure regulator to fix it.

[blue_cortina]

SO, the Carb fitted is an AUD368 which seems to fitted on some later cars. I tested the original brass float and it seemed ok - so I've put it back in along with original valve. Would like to have used a new valve but pleased to get it all back together. One of the reasons for rebuild was to try and resolve a poor idling problem, and I found a small piece of rubber in the inlet area which I think may have been a big part of the problem.

[philthehill]

The AUD368 carb was never according to the Burlen Fuels website fitted to the Minor. See attached list of applications

http://sucarb.co.uk/cf/vehicle/list/?ma ... icle=Minor

Burlen Fuels are the successor to SU.

I have not as yet found the original application for AUD368 and using the Burlen search facility AUD368 is not recognized.

Therefore I would suggest that the carb is not original Minor and has been sourced from a vehicle that utilized a HS2 carb. The swopping of carbs is not unusual.

The new float chamber valve could have been fitted without difficulty or causing additional problems.

[mobylette]

Phil

Back in 2014 you identified this carb as being fitted to the Austin/Morris 1100 (1098cc) Mk2/3 1971-1974 and the Austin/Morris commercial, 7cwt van, 1098cc, 1972 - 1973.

Martin

[philthehill]

Martin
Thank you for that.
I knew someone would come up with an answer.

http://sucarb.co.uk/carbspec/carburetto ... ls/id/285/

http://sucarb.co.uk/hs-float-kit.html

Note that the original float (not brass type but plastic) has been superseded.

http://sucarb.co.uk/su-hs-type-stayup-float.html

Phil