Six Pack Carb Fuel Leak

[bhthomas83]

I have a set of new Holley six pack carbs with the promax metering plates installed in the outboards. Ran the carbs about a year ago with a mechanical fuel pump everything was fine except the 2 middle cylinders on both sides read 300 degrees hotter than the outer cylinders. No matter what adjustments I made the temperature difference stayed the same. Long story short I bought a Fitech tri-power unit and converted to efi with an intake fuel pump. Never could get it to run right so I decided to go back to the carbs. Installed a regulator at 7 psi running to the carbs. The outboard carbs are leaking somewhere towards the bottom but I cant tell where. I've changed the gasket behind the metering plate thinking it was leaking there but that didn't help. Even when fuel is shut off it continues to leak until the float bowl is empty. I opened the sight plug on one and sprayed carb cleaner in it while it was off car and it all leaked out, it runs everywhere so you cant tell where its coming from. Anybody have any thoughts about where it could be leaking from? Nothing has changed except an electric fuel pump from when they ran and didn't leak a year ago.

 

[brian6pac]

Send me a PM tomorrow and I will get back to you

 

[Car Nut]

Too much fuel pressure.

 

[Demonic]

If they sat for a while, something dried out & helped with the leak. Bowl screw gaskets?

 

[72Dart6pack]

Too much fuel pressure. Why are you running those funky fuel lines? Stock lines work fine. Yes this is my setup picture. So I have experience on 6 Packs.

 

[Mattax]

I agree that 7 psi is pushing it. 3.5 to 4.5 would be good. 6 max.

That doesn't relate to external leaking out the bottom.
If they leak until the bowls are literally empty, on the outboard, the only thing is can be is the bowl gasket or the lower screw washers.
I realize that is a PIA to change.

The blue Holley gaskets are good. I touch them with a drop of WD40 to somewhat kill the sticky. That makes removing them easier.
For carbs where you're opening them up a lot, gaskets made of MP (?) material are probably better. I've got some of them in a carb right now.
For the bowl screws I use and reuse the black ones in the Holley kits.
Urich's 4150/4160 Carb Book shows fuel bowl screws should be torqued to 50 in lbs. This looks right.
I'll try to corroborate that later. I know there was one torque spec that's wrong in one of the books.

 

[Mattax]

As far as the EGT go, not sure how much weight should be put in them for idling. Fuel distribution at idle has alot to do with manifold vacuum, engine specifics and intake and exhaust. The fuel droplets are moving toward the lower pressure.

For WOT, distribution can be changed with spivies and notches. The replacement carbs are not the same as the OE carbs. For racing, the tips in the old DC bulletins are probably the place to start.