Fitting a NEW SU Fuel Pump

[Johnh]

Hello All,
I have been having problems with fuel smell and over pressure. I have now decided to fit an original SU pump which I now have. It seems to have 2 push on connections which look as if they are some form of vent pipe. The after market does not have these so I am unsure what I should connect to them. the electrics and the banjo connections seem fine. should I connect them together with a filter in the middle or are they some form of pressure release?
Help and advice greatly appreciated.
I can see nothing in the Repair Operation Manual or the Haynes manual and these connections do not seem to be in the illustration.
John H

Just re-looked at diagram and can see the 2 connections, one on the top next to the Lukar connection and the second by the connecting flange between the electrics and the mechanical parts of the pump.

JohnH

[wilf]

They are simply air vents for the internals, no connection to the fuel side of the pump at all. If you go and search on the Burlen website, you will find a lot more detail about these pumps.

Summary: Relax.

PS, you may find the banjos difficult to seal, I had to add some O rings on mine.

[Johnh]

Hi Wilf,

Thanks for the info and also for the link to Burlen.

I can now go and fit the new pump tomorrow.

John H

[022Dave]

PS, you may find the banjos difficult to seal, I had to add some O rings on mine.

Hello John,

Keep some extra banjo seals handy; they are a bugger to retrieve if they drop down the side of the fuel tank!

Dave

[Johnh]

Hello again,

Had an eventful morning got to local COOP, strong smell of petrol, I thought B********r it, hadn't fitted new pump yet and thought finally something had blown due to over pressure. Now the Carbs are giving me a pain with petrol poring out of the side of one of them, I think it is the Choke Butterfly, it is loose and fuel seems to be coming out of the hole through which the butterfly rod passes, seems a bit strange to me but more work to do now. Rescue service from RH was good arrived within the hour and took me and the car home.

Anybody know of a good source of re-con Carbs. I know the Gauge shop, and I have just found Andrew Turner, other recommendations would be welcome.

[jagorstag]

Hi John, that’s bit of a bummer for sure... You could of course also just buy a full rebuild kit from eg Burlen and do it yourself. I seem to recall a kit for both carbs is around 100 pounds or so.

You’ll find good step by step guides on how to do it in the ROM, on here (I think) and that Scottish site for which the name escapes me right now. There was also a guide in Practical Classics a couple of years ago.

Cheers,
Joakim

[mallardstag]

.... that Scottish site for which the name escapes me right now...

https://www.buckeyetriumphs.org/carburetors

[StagJonno]

There's this firm, Carb Care https://www.carb-care.co.uk/ . Used by Fuzz on Car SOS (for a pair of Aston Martin SU's I think).

Jonno

[richardthestag]

the world newest and best rebuilt carburettors will still overflow if the fuel pump is pushing too much pressure.

I found that needle valves in my stromburgs didn't like much more than 2psi pressure. My SU electronic pump was pushing nearer 5psi. Might not sound like a lot but an overwhelmed float valve will flood a carb and pour petrol outside! Filterking fixed it for me

[richardthestag]

if only the stag system had a feed to the carb and a return (smaller bore) back to the tank. Then something sensible could be used to pump and no overflow issues etc

[elvimto]

You can fit a tee into the system in the fuel outlet to the carbs with an orifice in the return leg to the tank I have done this I think I found it in this forum it does help. Also you need to have the correct pump 2.5 psi I think is the set point. SU does have different pressure ratings.

[DJT]

You can fit a tee into the system in the fuel outlet to the carbs with an orifice in the return leg to the tank I have done this I think I found it in this forum it does help. Also you need to have the correct pump 2.5 psi I think is the set point. SU does have different pressure ratings.

According to the Customer Services Advisor at Burlen Fuel Systems, the correct pump for the Stag is the AZX1308 which is a High Pressure unit set at 3psi (15 gallons per hour).

This is the reply I received in May this year:

Dear Sir,
The fuel pump you require is a AZX 1308 pump price £90.00 plus postage and vat .

Kind Regards

Stan Rawlins Customer Services Advisor

Burlen Limited - The SU and AMAL Carburetter Companies Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA Tel: +44 (0)1722 412500 Fax: +44 (0)1722 334221 Email: customer.services@burlen.co.uk Website: http://www.burlen.co.uk

[wilf]

Yup - AZX1308 is the model I have, works fine (once you replace the internal seals that degrade due to ethanol in the fuel - but a new one would have those already). Also has the correct pressure output. I suspect the terms "high and low pressure" on the Burlen website are a little misleading, having read all of the articles on there I think it is more to do with flow output.

[DJT]

Yup - AZX1308 is the model I have, works fine (once you replace the internal seals that degrade due to ethanol in the fuel - but a new one would have those already). Also has the correct pressure output. I suspect the terms "high and low pressure" on the Burlen website are a little misleading, having read all of the articles on there I think it is more to do with flow output.

The low pressure ones are 1.5psi.

[wilf]

Weird, the chap I spoke to there when I was sorting my "ethanol eaten innards" pump problems seemed to say there was some other meaning, but hey ho, so long as we get the right pump for our carbies.