I have an A15 which is almost finnished, but i have no fuel pump. Can anyone tell me if i can use the one from my A12 or A12A as i have these spare.
Cheers

i am pretty sure you can, they are no different i thought, i used my a12 fuel pump on my A14

Be careful ... the short-block and tall-block pumps are different (or maybe it is early vs. late engines). You could end up breaking the pump. Discussion: fuel pumps!

I heard that the A12a and A15 ones are the same because of thier position on the block (nearer the back), I have both as spares so i mite take a look and get back to you.

You have an american A12A, or a late-model A12? When you compare the pumps, grab the ID number as well off the block.

All the 1974 and newer engines have the distributor under #3 plug, and the fuel pump in the revised location.

Be good to know whether it's before-73 vs. after-73, or just short-block (A10/A12/A13) vs. tall-block (A14/A15)

The A12A, A13, A14 and A15 pumps have a longer arm than the A12. They may also have a heavier spring on the diaphram for higher fuel pressure. The cam lobe pushes down on the arm which pulls down the diaphram and compresses the spring. The spring itself expands, pushing up on the diaphram, pumping the fuel.
The A12A,13,14,15 pump will not fit the A12. I'm not sure about an A12 pump on the bigger engine.

i'm sure this was talked about previously due to someone putting an a12 one in and it kept breaking the arm i may be wrong but i am sure i read it just do a search for it. hope that helped

I reckon if youre using Webers or Dellortos go for a Facet Electric fuel pump regulated at 4psi and use a blanking plate where the fuel pump used to be situated.