Fuel pumps

[Philip J Wardle <Philip_J_Wardle@domain.elided>]

Hello Louis,

When I borrowed a MGB V8 once, which has a similar pump, I used to carry a
block of wood to bash the pump with when it stopped working ... I'm not
surprised that just playing with the contacts solved the problem (at least
temporarily).

The Stag fuel pump and parts is available new from Burlen Fuel Systems (tel
01722 412500), who have taken over manufacture from SU. I *think* the
correct part number for the contact set is AUB 6106, which is 14.38 pounds
+ VAT, which is what you need to replace your existing worn contacts.
Burlen will be able to check this is the right part for the Stag if you ask
them. Worn contacts are the usual reason pumps stop working.

The original pump AZX 1309 is now superseded in their catalogue by AZX
1307. The latest price I have is 45.00 pounds + VAT.  A rebuild kit is
available from the same source (part no EPK 300), which is 22.50 + VAT. The
Burlen catalogue is amazingly informative, it identifies many of the
individual parts within the pump and many are available individually.

The usual Stage parts vendors will sell you various alternatives, eg if you
look up the part no 150916 in their price list it directs you to 
AZX1311ALT "Fuel pump assy" at 48.12 pounds + VAT. Next to this entry is
AZX1311 "Fuel pump orig" at 87.55 + VAT, I'm not sure what the difference
is.

To answer your questions:

- These pumps are generally reliable until the contacts wear as you have
found out; there are kits available to reduce the wear which comprise a few
electronic parts mounted inside the bakelite cover but these are very
overpriced for what they are. I used to have an article in an Austin-Healey
magazine that told you how to make one, but I can't find it!

- To avoid weeping replace the banjo seals, Burlen can supply these. Worth
it just to get rid of that awful petrol smell in the car.

- I would replace the contact set only, not the whole pump.

- The pump contains a diaphragm which is pushed in and out by a
solenoid-type action (hence the clicks). Fuel is admitted to the diaphragm
chamber via an inlet valve from the tank, and is forced out through an
outlet valve. The full rebuild kit includes replacements for these parts.
When you first turn on the ignition the pump clicks quickly until the pipe
to the carburetters pressurises due to the float valves shutting off. As
fuel is used, clicking resumes in accordance with the rate of consumption.

Regards,
Phil Wardle

'73 Mark II with Mark I doors
Currently in lots of pieces