Carb troubleshooting

[MrMagoo]

Hey guys,

I have a new crate motor, with a new Quick Fuel SS-780 (vacuum secondaries) which is basically a Holley 4150. The motor starts up easily, idles pretty smoothly with 13 inches of manifold vacuum, but it quits when it gets to temperature (after about 5 minutes).

The fuel level in the sight glass for the primaries is 3/4 or more of the way to the top of the glass. The fuel level on the secondary sight glass looks like it doesnt make it up to the bottom of the glass, but there is fuel back there. QuickFuel documentation says they should both be half way up.

Fuel pressure is good, 6.5psi, coming out of a mechanical fuel pump.

After the motor dies, it won't maintain idle again until I wait quite a while, like when it cools down. One other symptom: it doesn't appear that fast idle is kicking in like it should after I start up.

I know about backfires and power valves, and I did have a backfire due to a loose spark plug wire when I first started running the motor, so I was wondering if this could be a symptom of a blown power valve.

I just bought a holley book and borrowed the DVD, since obviously I'm going to have to learn something about these carbs, but I was would love to hear from everyone about where to start and what to look at.

Thanks!