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Discussion Starter #1
Holley SA 770. It was running fine right out of the box except for being a bit rich. Lucky me. But now that I’ve swapped rears I’ve got a very noticeable bog when I stomp on it. Of course changing one thing always affects other things. I’ve got a selection of squirters and pump cams on the way and hope to get it dialed in this weekend. Considering my engine is on the mild side I’m guessing my 30cc pump will still handle the job.

Correct me if I’m wrong, but since I’ve got an instant bog instead of a jump-bog-go situation, a smaller squirter should be in order? Stock is a 31 and I’ve got a 21, 25, 28, and 35 coming.
 

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Sounds like your on the right track with the squirters for the bog. You mentioned a rich condition which may be corrected with smaller jets. That can help. Check your plugs to get an amber color too.
 

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rich at idle, transition, cruise, or WOT ??
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make sure the squirter is coming in as soon as you touch the throttle..
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was it good and warmed up?? .richen it up a little for winter yet ??
check for Vacuum leaks yet ??
got a Vacuum gauge ??
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where is the transition slot ??
too much idle screw will uncover it, and create more/same/other problems..
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idle timing and advance??
a little more timing at idle helps everything, almost every time..
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usually the complaint on the SA is Lean ..
here's a long, but good read
https://www.hotrodders.com/forum/holley-670-vs-street-avenger-hesitation-fix-507033.html
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:texas:
 

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Discussion Starter #4
This Carburetor is rich throughout the range. And yes, of course, everything checked when warm. No vacuum leaks. Yes; I have a vacuum gauge and even added an under-dash vacuum gauge to aid with tuning. 18° Initial advance and 35° total advance. All in by 2,500 RPM. I’ve tried a bit of vacuum advance also, even though the engine builder recommended no vacuum advance. I've already reduced the primary jets by four sizes. No need for winter enriching here on the CA coast. I’m about 35’ above seal level.

Car actually runs great, but my Innovate wideband A/F gauge tells me it’s too rich. Reducing the main jets brought the cruise up from the mid-12’s to the mid-13’s. WOT is mid-11’s. I’ve recalibrated the O2 sensor twice with no difference in readings. Plugs look fine.

My only real problem is the new bog when stomping the gas which manifested when I switched from the 3.73 gears to the 3.00 gears. I’ll play with squirters and cams first and maybe switch to a 50cc pump if I can’t fix it any other way. My gut tells me to go with a smaller squirter, but at only $15.00 per, I ordered one a bit larger also just to make the process quicker if I’ve guessed incorrectly.
 

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if its fat all over
it could be fuel pressure, float level, blown power valve, bad gasket, plugged air bleed....
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are you running a PCV with a good crank case vent??
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pull a vacuum hose off, and lean out the o2 sensor, it may help clean, burn off
any contamination from runnin rich for a long time..
I have a small needle valve I put on a manifold vacuum port for checking/testing/tuneing...
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a lot can depend on if its a true dual plane intake, with true dual exhaust and 1or2 o2 sensors??
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x2 on the Vacuum advance on a street car, usually makes things better..
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:texas:
 

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Discussion Starter #6
I was actually starting to wonder if my A/F meter was bad. But today I spent several hours changing jets to extreme limits and test driving while comparing seat-of-the-pants to the meter. It seems to be reading properly. Eye-burning rich mixture reads around 11:1 and lean surging shows 16:1. So at least I know the Innovate meter is correct.

After a long day of messing with it I’ve determined that my engine really wants to cruise in the 12.5:1 to 13:1 range. I was hoping I could get it cruising in the 13.5:1 to 14:1 range, but it was not to be. I ended up only two jet sizes down from stock on both primary and secondaries. Tomorrow is pump squirter day....

Once upon a time I told myself I’d never own another carbureted vehicle. I must say that I was really contemplating just pulling the trigger on a Sniper system today. And I still may. But for now the carburetor is working at an acceptable level.

Thank you for your input.
 

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Thank you for your input.
lol... im just tryin to jog your memory, sounds like you been around the block at least twice.. lol
except for the smaller squirter for the stumble , I don't under stand..
I was thinking a faster cam first then a larger squirter,, or depending on the secondary spring?? maybe a stiffer one,, if its part of the problem??
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on the PCV I was wondering if its mandatory in Cal.,, and the EGR too.. just wondering??
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:texas:
 

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transition slot is where I would start and sense you got the O2 Wideband and vacuum gauge just keep dialing it in. It takes a lot of tweaking to hit that 12.5: Good idea to check your valve lash. whaasup:
 

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Jeff Smith, author and El Camino owner, in a recent article discusses correcting a Holley accelerator bog that can be caused by fuel additives (blended fuels). See Item 3, Accelerator Pump Fix, in this list of 10 tips.

Featured on www.enginelabs.com
Jeff Smith’s Top-Ten Tech Tips – Ideas You Can Use Right Now
By Jeff Smith May 09, 2019

https://www.enginelabs.com/engine-tech/jeff-smiths-top-ten-tech-tips-ideas-you-can-use-right-now/

If you see at the top of the article, an image of a group of Jeff's friends around the engine in an orange Chevelle, that is another NECOA Member Eric (FauxRS) on your left.
 

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Discussion Starter #11
lol... im just tryin to jog your memory, sounds like you been around the block at least twice.. lol
except for the smaller squirter for the stumble , I don't under stand..
I was thinking a faster cam first then a larger squirter,, or depending on the secondary spring?? maybe a stiffer one,, if its part of the problem??
.
on the PCV I was wondering if its mandatory in Cal.,, and the EGR too.. just wondering??
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:texas:
CA doesn’t require smog checks on anything older that ‘75. But I do run a PCV system. It’s been a long time since I’ve had to screw with accelerator pump squirters. And I was wrong. The go-bog-go is generally a symptom of too large of a squirter. The no-go then go is generally from too small of a squirter. Changing from 3.73 gears to 3.00 gears gave me the no-go then go symptom. Going up a few numbers took care of it.
 

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Discussion Starter #12
I forgot
yesterday I was going to say try lowering the front float level a little and
see if the whole fuel curve changes or acts normal.. just as a quick test..
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:texas:
I’ve played with float levels on both ends. No real noticeable change between mid-glass and just visible at the bottom of the glass. Fortunately I’ve got things dialed in pretty well now and I’ve got both set with the level about 1/3 the way up the glass.
 
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