Fuel Return on A 502 Mag, EFI?

[LazyLavey]

A friend has been having random vapor lock issues (or at least the symptoms) on his 2000 502 Mag Efi. Basically stock (headers and MSD)

A questionable source advised him to add fuel return lines to solve the vapor lock. He has already replace the fuel pump and cool fuel but still occurs maybe a few times a year...

So he's thinking an Imco 6 port valve

Anybody got any input as to the validity of the return lines solving the issue?

Or any input for that matter

 

[25Elmn8r]

I had the same symptoms in my Daytona. Start and run fine, shut it down for random amount of time, then won't re-fire. thought it was vapor lock, but there was fuel in the rail.
When it won't fire have him check the schrader valve on the front of the rail, my guess is there is cool fuel and no vapor.

Turned out it was a problem pulling fuel from the tanks. Added an electric pump to pull fuel from the tanks to feed the hi pressure pump on the motor. Never had the problem again. And yes I tried a new pump on the motor before adding the second pump.

 

[mswasey]

I had the same symptoms in my Daytona. Start and run fine, shut it down for random amount of time, then won't re-fire. thought it was vapor lock, but there was fuel in the rail.
When it won't fire have him check the schrader valve on the front of the rail, my guess is there is cool fuel and no vapor.

Turned out it was a problem pulling fuel from the tanks. Added an electric pump to pull fuel from the tanks to feed the hi pressure pump on the motor. Never had the problem again. And yes I tried a new pump on the motor before adding the second pump.

I had the same thing on my ‘99 500EFI. I did the same and added an electric pump close to the tank and no issues after.
As a bandaid, you can run fuel without ethanol. I did that for a while and it never vapor locked, it’s just impossible to find non-ethanol fuel mid lake at Powell!

 

[85RiverRAT]

We got rid of the VST on our 95' 502 MAG. We have a separate fuel filter, water/sep., and an Aeromotive electric fuel pump, mounted to the stinger, supplying fuel to a regulator mounted near the fuel rails. On the older mags, the fuel rail are pressurized in a loop, fuel goes in from one side, and out the other rail. Ran a return line back to the tank, the fuel rails accepted standard AN fittings. No issues. The electric pump is constantly pulling cool gas from the bottom of the boat. The mechanical lift pump got a block off plate, and we tossed the VST in the trash.