What would make a carb SHOOT gas through the front vent tube? It's a Holley dual ifuel inlet vaccum secondary. I'm having problems. Further reading here: https://www.thirdgen.org/forums/tech...-overhaul.html

 

Excessive pressure from the fuel pump, or dirty float needle/seat.

 

five7kid & some others were right by wanting to check fuel pressure.

I had the same problem as far as the vent tubes looking like a wildcat oil strike!! Our carb is a Holley single pump, dual feed. Our pump is a Holley Blue elec. When I was able to have someone with a pressure gauge come over, the pressure was well above 7 lbs!!!

Baffling to me is if it's shooting the out the tubes, how the sight glass would seem ok.

Maybe tap the bowls with something similar to a screwdriver handle to jiggle stuck floats..?.. Not hard like your hamering a nail, but kinda firm like you're about to swat an easy kill fly.

 

Aside from disassembling the carb, how would I claen the needle and seat? Maybe spray some carb cleaner through the fuel line with the throttle opened? This carb does have blue gaskets installed so I could disassemble it if I knew what I was doing.

I reused my stock fuel pump so my pressure SHOULD be fine, right?

 

you need the correct fuel pressure. you don't want to disassemble the carb if you don't need to.

 

No. The float tends to trap the needle against the seat with whatever crud is causing the problem, so in order to get it to clear, you at least have to get the bowl empty, then hope the debris is flushed out when you allow the fuel to flow again. Sometimes works, most of the time disassembly is required.

Probably, depending upon what "stock" is. Very likely you got crud in the fuel line and drove it into the needle/seat when you tried to start it. Do you have the filters in the inlets behind the fuel line nuts in the fuel bowls like Holley requires? There should be a spring behind the filter to hold it against the inlet nut.

 

Are you using the stock fuel pump from a TBI, TPI or EFI controlled carb?
If you are that is the reason... That is putting out like 40psi of gas when you need 5-8 psi...
You need a return style regulator like a MAllory 4309.

 

Ok so I pulled off the carb and laid a rag over the baseplate and when I cranked the motor it blew the rag off. I now know why the carb is shooting gas, but why is my intake manifold blowing air instead of drawing air?

 

Lost!! If the exhaust blows & the intake blows, IDK what to think!

I would guess the cam & crank gears were 180* off, but if both intake & exhaust blow out, ....

 

I know!!! It blows really hard through the intake in pulses, and not nearly quite as hard through the exhaust, but still in pulses. So WTH is going on here? I am thinking that I may have some severe overlap. As in both the intake and exhaust valves are open on the compression stroke. IDK but my only option it seems is to pull the front of my motor off and recheck my timing set's accuracy. So WTH do I do when I tear it all apart and the dots on my cam and crank line up like I fear they will?

 

With the dots lined up--
cam dot at 6 o'clock
crank gear at 12 o'clock
IIRC is #6 at TDC compression. I'm not 100% sure where #1 would be.
Still tho, it would'nt cause the intake valves to blow out instead of in.

But still it would pop & backfire, being 180* off. There would be some signs of life.

Can you post the cam grind you're using & brand?

Did you seal the fuel line threads with teflon tape, & if so, how much did you use? A stray piece of teflon may have found it's way into the bowl(s). That would also cause some plugging of internal passages in the carb.

I know you're frustrated, & none of this explains blowing out the intake.