98 vortec carburetor swap

[Wintergreen98]

I put a 750cfm carburetor on my 350 vortec along with all the other stuff needed to do this swap but my carburetor pours fuel out of the vent tube right before it shuts off. I adjusted the fuel regulator just barely and now it's almost like it's not getting enough fuel to carburetor. I need suggestions on how to fix this. I'm using the stock fuel pump that comes on the truck and an off brand regulator off of ebay.

 

[Supercharged111]

You need to post a lot more about your setup, like pump, regulator, ignition, etc.

 

[Schurkey]

Perhaps a moderator will move this to LSX + Carb Swaps.

 

[kennythewelder]

The thread has been moved.

 

[DerekTheGreat]

Sounds like your float bowl isn't adjusted properly. Fuel coming out of the vent tube suggests that or the needle is sticking and not seating.

Is this an old carpitrator? Too much fuel pressure coming into a carburetor can over power the needle & keep it off the seat as well, which will cause fuel to dump out of the vents and boosters.

 

[kennythewelder]

It is not necessary to ask the same question in two different places. From what you describe, it could be a few different things. To much fuel pressure, sticking float, just to mention a few. I will say this though. 750 CFM is to big for a 350, of 5.7L you need from 600 to 650 CFM for that size engine.

 

[Schurkey]

my carburetor pours fuel out of the vent tube right before it shuts off.

What carburetor?

Does this mean the truck runs good, then floods and stalls? Or does it mean the truck runs so crappy it won't stay running?

I adjusted the fuel regulator just barely and now it's almost like it's not getting enough fuel to carburetor.

What is the fuel pressure? Does the carb still flood, or is that problem solved?

 

[Wintergreen98]

It runs good then floods.

 

[Erik the Awful]

It runs good then floods.

You need a return-style fuel pressure regulator. They're about $40. The cheap fuel pressure regulators are designed to dead-head with no return line, but the stock pump can produce enough pressure to overpower the spring.

 

[Wintergreen98]

Mine has a return port on it but I still need a different regulator. I have the same regulator that's in the picture.