i got a Holley 670 Street Avenger...everything is fine..starts good, runs good, just everytime i give it the gas, it stumbles bad...almost to where it wants to die....besides adjusting the accelerator pump, float levels, and mix screws...i've got a fuel pressure regulator, so i got good pressure...what else is there that i could do??? no black smoke, doesn't run rich...i'm so fed up!

 

Adjust the butterflys per Lar's and it should clean up. Did for me.

 

vacuum leak?

 

Where is the info on the butterflies? I didn't see it in Lars paper on tuning Holleys.
Or did I miss it

Pat

 

Does this Holley come with the internal gas filters like my 750 dp, if so get rid of them and put an inline filter on or just check your inline filter it maybe dirty.

 

inline filter is brand new...the street avenger is suppose to be bolt on and go! what do i adjust the butterflies to?

 

Speed Demon 650 should fix that :cheers:

 

Hi
i also have the 670 street avenger. i had less than a hundred miles on it when it suddenly started to stumble really badly every time i gave it gas. It turned out that the accelerator pump discharge nozzle was blocked with dirt.
It took about ten minutes to fix as you can remove it with the carb in place (just don't drop it inside the carb!!) You can easily check it is working by pumping the throttle and watching petrol squirt out of the nozzle. It may be even if petrol is squirting out that you have a partial blockage so its worth 10 minutes just to take the nozzle off and blow it through with an airline.


:seeya

 

:nonod: sorry, had it, and hated it!

 

Hmm maybe it is a more serious problem.....Just curious why you hated the Demon? :cheers:

 

:iagree:

I love my Demon. Works great!

 

You might try unhooking/wiring your sec closed just to rule them out. Then look at the powervalve, I am going through it myslef and trying to use vac adv at idle to smooth my idle. Driving me :crazy: .

 

Alwyn...the Demon was awful! the screw to adjust the back butterflies wasn't on there, it ran way too rich all the freakin time! the choke always got caught on the air cleaner base and made it run FAT all the time....it was hard as hell to start! i may have just gotten a BAD demon....but i was glad to get rid of it.

 

REDSHARKY sounds like the new carb is again the problem child. Now I can't silently follow this delimma and have to say something. I don't know what altitude Hurricane WV is at but I do know that a Holley jet change is needed for every 2,000 feet of altitude change. But if you are higher it should be running richer (black smoke). You maybe able to verify this on thier website (Holley) but may need a "How To" Holley carburetors book (David Emanuel). The way I remember it a carb/engine stumbles only when drunk with fuel but you stated no black smoke so from out here in California it looks more like a lean bog. :jester Lean to me means lack of fuel soo to make a list:
1) clogged fuel filter, line, jet, accel pump nozzle
2) vacuum leak, bad gasket(s), filltings/plumbing/hoses
*3) Too light a spring in vacuum secoundary diaphram allowing secoundarys to flop open and bog you down and somehow I think this could be the trouble maker.
4) I don't suspect the power valve due to high altitude or maybe a blown PV diaphram keeping it shut but on a brand spank'n new carb - I doubt. I could be wrong (again) but I remember the PV as staying shut until manifold vac. is low (high load/open throttle) and then opening to increase fuel flow to jets.
Sorry but I kind'a trust factory butterfly settings on a new carb and doubt I could do better.
Now the $400 question: is this the same problem/symtoms as the "Demon"? If yes my guess is problem outside of carb and in fuel line or vacuum lines/plumbing or gaskets. :seeya