Hi folks,

Well I seem to have resolved my starter motor problems. After managing to get the plug leads correctly sorted (the usual "180 degrees out" TDC problem), I now find the dreaded SU auto enrichment device is flooding with lovely black smoke filling up the garage and fuel leaking everywhere.

Just wondering if this could be an assembly problem or just a matter of adjustment?

Any help appreciated (again).

 

Check you needle valve on the front carb and make sure it isn't sticking open.
Adjust your float level.

If you're running Gross needle valves, they can become sticky.
I had some in there and after siting for a long period, I never did get them "freed" up.

 

Hi, although I have experienced the AED flooding and sneezing fuel from its nostrils, you'd only get an over rich condition if the solenoid valve was open in the AED itself. If the valve is open (evidenced by the hissing noise) disconnecting a wire from the AED should close it. Otherwise if the AED has been removed it is possible the disk at the end of the rod or the spring behind, or the AED body itself, hasn't seated properly

 

Thanks for the replies gentlemen.

Upon further observation, and with the needle removed, I cannot see any jet device at the base, and when inserting the needle by itself, I fail to see how it would close off the fuel supply, irrespective of what position its in. Also, when opening the throttles, there's a sudden backfire with fuel spewing out, severely!

So, I have ordered a new jet, needle & spring from Burlen in Wiltshire (very helpful people) and will report back asap.

 

The AED is a fairly crude device, and there is nothing to stop it being supplied with fuel other than the front carb float chamber valve. Hence if the float chamber fuel level is correct the level in the AED when it is disengaged is set by gravity and you can do what you like with the needle without making any difference. Aside from the float level the only way of adjusting fuel is to invert the connecting piece that passes fuel from the float chamber. So it might be worth checking that it runs uphill rather than downhill. Although the fuel supply cannot be isolated, the fuel can't get to the inlet manifold unless the AED soenoid valve is opened. If the valve is closed any excess fuel can only overflow from the "nostrils", in which case it won't in itself make the engine run richer.

Another thought, if the ignition timing is too far retarded this would cause backfiring which can in turn flood the AED. I think if I were designing an AED today I would incorporate 2 improvements, variable operation of the solenoid to reduce the enrichment as the engine warms, and an electronic valve to shut off the fuel supply to it when it is disengaged.

 

Auxiliary Enrichment Carburetter (Thermo) - SU Carburetters

This may help with understanding how it works and add pictures to CD2005's description.

 

Thank you guys, that info is of immense help.

I did not realise the connecting piece which delivers fuel from the front carry was reversible, and its quite possible I have fitted it incorrectly when I was fitting new jets to both carbs upon overhauling them. I also think the workshop manual may be silent on that particular issue.

Last night, working in garage the cold Canberra winter, I banged my ear on the RH bonnet/hood hinge (bonnet removed for ease of access) and by God, did it hurt.
At that stage I was ready to push the car over a cliff................

 

I remember playing out side in the snow when I was a kid and banging my ear...
Yes it does hurt !
OUCH !!