N8Miller

ok, the holley avenger 670 carb is allegedly not opening the back secondaries at all. why would this be? how can we fix it?
oh yeah, we can see the fuel in the secondaries area in the clear bubble thing on the side, but its not shooting any fuel in there at all. my cousin make it go full throttle, ,then stuck a q-tip in there to see if any gas was getting in there at all-------none!!!
what can we do guys....please help asap. could it be a vaccum leak?
if its fixed by tommrow, were gonna take it to the track?

Jester

You can't tell if they're opening or not short of watching it run on a dyno. I've never heard of anyone trying to stick a Q tip down there either....but I seriously doubt it would work and even trying is a bad idea.

Unless the diaphram is torn or there is a blockage in the port...both of which are easy enough to check...it's prolly working.

F-BIRD'88

You will not see the secondaries open by reving the motor up in neutral. No matter how hard you try. There is a built in delay
to prevent too early secondary action to prevent bogging.
The secondaries only open at full throttle while the motor is under load, Like driving down the road.
The only thing that can go wrong with the vacuum secondary system is if the diaphram is torn or the gasket between the vacuum pot and carb body is missing or the vacuum passage is blocked. Not likely, especially if it's never been apart. You can buy different springs to adjust the sec opening timing and rate,
but the motor will open the secondaries as much as it needs to.

BigL350

The secondaries most likely are opening. Change the black spring that comes in the secondary diaphram for the yellow spring. It's the better spring for a performance application and you will feel the secondaries a lot more.

82z28122

iTrader: (1)

yeah change the spring. You will feel a slight differance, but why do you think they are not opening. You might just be like me and want more power and are looking for any excuse.

N8Miller

on the need for power----your right there.


Ok, we swapped out the spring for the Yellow one. result: could feel the carb more. not bad.

Now: lowered the fuel volume in the front bowl, but we cant lower it in the back one. it is backfiring like a beotch, and we think that becasue the back one is now totally full, it is running too rich and backfiring------is that correct?
got any tips for lowering the back bowl? we have the directions, but when we do that, it dont seem to work. but, when we take the screw and adjuster nut up higher, the fuel pressure goes right to where its supposed to be. but when we screw them back down, they raise again. need some help here.

PS, i now understand about the secondaries---thanks for the help everyone