new carb hesitating a bit

[GregWeld]

I just put a brand new out of the box Holley 650 on my buddies '32 Ford... got it running fine but not "perfect". I thought it was pig fat cause it felt a bit lazy in the bottom end... and it had a bog if you jumped in it.

Bottom line was -- we took it to the dyno -- it wasn't pig fat -- it was LEAN -- and needed the squirters resized (drilled out) and two jet sizes bigger in the primaries...

Here's what I'm trying to say:

Some of this stuff takes a pro and takes equipment (tail pipe sniffer etc) to sort out even if you're real familiar with carbs and timing etc. You could spend days trying to sort out all the advice and tips you're going to get in forums like this.

[v8s10kid]

i have no way of telling if its rich or lean. i dont have a timing light or a vacume gauge.

it does it in both normal and full throttle driving.

i got new plugs ill change em tomorrow and check a few more things but if i cant find it one of my dads friends builds and races modifieds at the local circle track, hopefully he can sort it out.

normal driving it has a lack of power and seams to bog a bit. full throttle it hesitates till about a quarter up the rpm band then it suddenly has this massive release of power. when i let off the gas it does pop and sometimes backfires.

[Ron in SoCal]

Originally Posted by GregWeld

Here's what I'm trying to say:

Some of this stuff takes a pro and takes equipment (tail pipe sniffer etc) to sort out even if you're real familiar with carbs and timing etc. You could spend days trying to sort out all the advice and tips you're going to get in forums like this.

What Greg said. I had a new Holley 750 do the same thing you're describing. I spent hours trying to get it right, with help from so called 'carb tuner' friends. Took it to a tuner, ran great right after that. Good luck...

[chr2002ca]

I had the same trouble with 3 new Holley carbs. Two 750 Vac Sec models and one 770 Aluminum Street Avenger model. All 3 had a bog and WOT on a new engine. I had to bump up the squirter size 2 or 3 sizes, change the accelerator pump cam, install a larger CC accelerator pump, and change the vac sec spring. I also bumped up the primary jets one size. After that, the bog disappeared for the most part, but then it ran rich only on idle. I had to do some other tinkering to get the idle to not run rich(was fouling out my plugs), but those are unrelated to the bog issue discussed here. In summary, it took a lot of work to get the carb running right. I could not have done it without installing a FAST dual A/F metering system. I wish you good luck with yours.

[exwestracer]

X2 on the lean condition. You will almost never see a bog from being rich. We were chasing the same thing on a Camaro here at the school.

Are you running an adaptor on the manifold? We found some serious vacuum leaks under the carb with the el cheapo adaptor the student had on the car.

[v8s10kid]

yah, ill ahve to have my dads buddy tune it.

no, no adaptor.

did have a misshap. sence it is my daily i had to drive it to work today. i wasnt beating on in or anything. it backfired on the ighway and blew out the exhaust flange gasket i just fixed.

it sucks trying to do this crap when i have to drive it at least an hour of highway miles the next day.

[v8s10kid]

changed plugs, better still doing it tho. hopefully the mechanic will let me stick around so i can learn some $#!%

[v8s10kid]

cant get it to the mechanic so i did some more checking. also adjusted the idle mixture screws a bit.

-20 inches of vacume at idle (was 18 before adjustment)
-the accelerator pump nozzle is spraying a pritty thick stream of fuel
-changed vacume secondarys from silver to long yellow spring (lighter)

still need to check the floats and borrow a timing light from someone to check the timing. but i have to go to work , hope its at least better now.

[v8s10kid]

new msn cap and rotor, better but still there.

float levals are good, and as i said i got 19.5 inches of vacume on idle.

gona see if i can steal *ahem* i mean borrow someones timing light.
what do you guys think timing should be?
1983 305 H.O.
edelbrock performer intake
holley 570cfm street avenger
stock hei with:
-msd coil
-msd cap and rotor
msd wires
shorty headers
2.5 inch flowmaster exhaust

also, idk if this matters but the timing tab is straight above the balancer behind the water pump

[v8s10kid]

its a bit cold out but i finally decided to suck it up and check a few more things before i go spending $ all crazy like. holleytv.com gave me a few starting points

fuel filter - good
air filter - looks good but will run it without it to double check
egr valve - dont have one
alt voltage - good (at battery:12.9 volts when off, 14.8 volts when at idle)

as i was checking the alternater to see if maybe the ignition system wasnt getting enough voltage i could hear a metallic sound coming from the passanger side valve cover. not a constante noise but you could hear it every now and then. oil level is a bit low, im hoping its just a rocker not getting enough oil or that has too much lash.

ill have to check the valvetrain when i get home later