I have early 500 efi,s that vapor lock. They do not have the mechanical fuel pump on the raw water pump just the electric pump on the cool fuel. Now all my 390 velocity,s had that mechanical pump and never ever vapor locked . I think instead of pluming in 2 electric pumps closer to the tank I'm going to swap out the raw water pump for the style with the fuel pump on them and use all factory . hardware. I like stuff the way it came from the factory.

Just install the Merc booster pump kits OR run a return line back to the fuel tank.

Do they still make those pumps? I have a set on my phantom . They tie right in to original harness. Forgot about that .

I have to look and find the part no .

I have 2 of the sea water pumps that have the fuel pump mounts on them I would trade for your pumps without them. I'm not using the mechanical pumps and was planning on just putting block off plates on them.