You can start by cleaning the points. To do this properly, you will need to loosen the screw holding the upper points in place, remove the spring blade with the contacts and scrub the contacts well on a small sharpening stone or a piece of 400 grit sand paper placed on a flat, hard surface. Once the contacts are bright and shiny, replace them on the pedestal and tighten the screw. For the lower contacts, you will need to remove the two screws that hold the pedestal in place, and carefully fold the pedestal back around the pivot pin through the pedestal legs and the lower points toggle so that the contacts are exposed. Again with the small sharpening stone or the 400 grit sandpaper wrapped a small piece of steel bar, scrub the contacts until they are bright and shiny. Fold the pedestal back into place and replace the screws. If the points are not worn too badly, this should get you running for at least a couple of years. You can get a rebuild kit from Victoria British - P/N 3-2059, but you will need to ask them what the diaphragm spindle length is, there are two lengths - 2 3/8" and 3", depending on what length the coil housing on your pump is (they will be close to the diaphragm spindle length is.
Another alternative is to look in the Links section of mt web site at:
https://homepages.donobi.net/sufuelpumps/ under SU Fuel Pump Repair/Restoration and pick one of those people to send your pump to for repair/restoration (I am out of the picture until the first of Oct.).
Cheers,