carb gurus....need advice

[dragnazz5.0]

alright, the combo is a 306, slightly ported stock heads, tfs 1 cam, 1.7 rockers, air gap intake and edelbrock 600 carb. the carb has the 8 in/hg step up springs, .101 main jets, 7047 metering rods and the idle mixture screws are about 2 turns out. now my problem....its got a tip in stumble/hesistation. ive tried backing the idle screws out more but it doesnt help. ive changed jets and rods just in case they would help also but nothing. i dont know where to go from here. the car has 16 in/hg for vacuum and idles fine and drives great except for this problem. i guess really the only thing left is a vacuum leak or rebuild the carb or get a new one. someone give me some opinions or advice...thanks fellas

 

[Modular2v]

if you have been tinkering with it that much and nothing had improved it chances are the whole thing needs a overhaulin or just get a new one

 

[bt15]

Is the problem on your initial tip-in or are you talking about during secondary actuation? You probably mean initial tip-in based on what I've gathered. That being the case, what size shooter is your primary? Have you changed it from stock? If not, you may need slightly more. For example, if your stock shooter was a 31 and you have made mods to your car, you may need a 35 or more. There's also the Edelbrock Tech line if you are so inclined. I'm running a Demon carb now, but the Edelbrock guys were pretty helpful when I was running an Edelbrock.

 

[dragnazz5.0]

yeah its a initial tip in problem. everything on the carb is factory so i dont know what the primary squirters are.

edit:i just realized i left something out that i had found today. the motor was fully warmed up when i was working on it today but i noticed when i got the air horn off there were bubbles coming out of the primary jets....not huge bubbles but just small little bubbles coming out for maybe 10 seconds after i got the cover off.....is that normal or does that mean there is something leaking somewhere?

 

[Modular2v]

have you checked the power valve? metering block gasket?

 

[feifong]

i have the same 306 but with afr heads, tfs1 go with a bigger carb 670 sa should help a little. Its the intake its made for higher rpms thats where youre hesitation might be. Go with a weiand or upgrade to bigger carb and fuel pump. just my opinion

 

[89lxcoupe]

well i've always run a holley 650 dp at the biggest 750, on most 302 setups they like about a 1 inch - 2 inch spacer between the carb and intake to get the tip in stumble to go away, that always fixed my problem with the tip in stumble. but also going up with the squirter a couple sizes will help ! just my experience.......

 

[dragnazz5.0]

ill have to try that spacer idea. other wise im gonna see if my boss will let me buy his holley 650 double pumper

 

[Modular2v]

a dp is the way to go anyway

 

[dragnazz5.0]

does anyone know anything about the bubbles coming out of the jets? im just wondering if this is normal or if there is something wrong

 

[bluevenom867]

Fuel percolation,try putting a heat insulating spacer under the carb.

 

[dragnazz5.0]

thats kind of what i was thinking but couldnt think of the word. im gonna try to put a spacer on it and see what happens