By Roddy Phillips (March, 1997)
Replacing the fuel pump in a carbureted P1800 is a fairly simple process if you have the right parts at hand. Make sure you have replacement hoses and clamps for any you will be removing, as well as two new gaskets, a new spacer block, and some silicone gasket sealer.
Although the fuel pump contains a strainer to remove large particles from the fuel, it is a good idea, especially in an older car with a rusty gas tank, to purchase an aftermarket fuel filter to place in the fuel line. Of course, if the car is completely original stock, an in-line filter will not look right. More often, P1800 owners have done away with the original fuel pump and lines, and an in-line filter can be fitted easily. I've used a small glass Purolator with replaceable filter element for many years.
Only two bolts hold the fuel pump to the engine block. Since the fuel pump is constantly being heated, cooled and vibrated, it is no wonder that most B18 and B20 engines leak oil around the fuel pump flange. This is where the silicone sealer comes in. I generally don't use gasket sealer because it's a pain to remove when you need to replace a part, but this is one place where it is necessary. First clean the engine block mating surface with clean paper towels soaked in a quick-drying solvent like Berryman's B-12.
Don't use the old spacer block. If it's not cracked already, it might well be if you re-install it. A new spacer is inexpensive and clean enough for the sealer to adhere to.
Apply a small, continuous bead of sealer on both sides of each gasket, being sure to encircle the bolt holes. You need four hands or a lot of patience to get one gooey gasket on either side of the spacer block and keep them aligned with the fuel pump as you insert the drive lever into the engine block. Aim high with the lever -- it should ride on top of the camshaft. Tighten the bolts no more than fifteen foot-pounds. It's tempting to overtighten them, but remember that the sealer will take care of oil leaks.
Let the sealer set for an hour before starting the engine. This will help it seal, and give you time to do a neat job of replacing the hoses and clamps.