Holley Carb Tuning

[Mr. Land Yacht]

so, I got a Holley 4160 Carb on my MAGNA 302X...and being that I'm 21, I dont know anything about tuning carbs.

its got an electric choke and vaccuum secondaries.
here's some pics for reference








so, right now the biggest problem it is giving me is a super high idle...I pump it one small time and fire it up...turns on and revs to 2K...so I tap the gas and it go down to like 1800-2K...
I've turned that hockey puck looking thingy all the way lean(clockwise) and it doesnt make a lick of difference...the fast idle has gone down to more like 1600 when I tap the gas, but that's it.
I dont mind a fast idle, I just dont want it to get above 1600rpm...and it takes forever to warm up the choke...anything I can do about this?

oh, on a side note, I'm starting to get a little bit of popping when I accellerate....timing?

[Archangel]

popping - got a vacuum gauge and a timing light? What's the color and smell of the exhaust fumes?
fast idle - look at attached pics, stuff circled in red, back that screw out some

[Mr. Land Yacht]

ah..thanx Ivan..I thought so, but its hard to get to, cant see it when its attached.

how far to the left/right should that hockey puck thing be?

[Lincolnmania]

why are you trying to adjust idle with the choke?

[phayzer5]

How used was that carb when you got it? Id first make sure that the timing, floats, and idle mixture is set right before going right for the tuning. Check for vacuum leaks, they will make the engine idle higher. Take the electric choke out of the equation for now, The car will run fine now without it. Wire-tie the choke open and get the idle set right.

This along with a jet kit will make your time tuning easier

Silly wabbit, chokes are for kids

[Archangel]

why are you trying to adjust idle with the choke?

He ain't - his fast idle is set way too high, and fast idle is engaged when the choke is - he gots electric choke so when he starts cold his choke is engaged, whether he wants it or not. Also I disagree with Justin's idea of wiring choke wide open - MI ain't no FL, tis pretty darn cold in the mornings, and Colin uses his car to get to and from work.

[Archangel]

ah..thanx Ivan..I thought so, but its hard to get to, cant see it when its attached.

how far to the left/right should that hockey puck thing be?

Yeah, tis a bitch, get used to it How much to turn it - till yer idle goes down to where you want it, trial and error kinda stuff.

[Mercracer]

I've turned that hockey puck looking thingy all the way lean(clockwise) and it doesnt make a lick of difference...the fast idle has gone down to more like 1600 when I tap the gas, but that's it.
I dont mind a fast idle, I just dont want it to get above 1600rpm...and it takes forever to warm up the choke...anything I can do about this?

The hockey puck thing is an electric choke thermostat. It needs switched 12V applied to it and it needs a good ground. They wear out over time and need to be replaced. Set your high idle by turning the idle screw which rides on your high idle cam behind your choke thermostat. If that screw is off of your high idle cam, then your regular idle screw needs to be adjusted. If that is unscrewed all of the way, then you could have a vacuum leak. There is no reason to just lock your choke open.

[Mr. Land Yacht]

ok, I'll adjust that screw if I can get to it.
thanx

[DuceAnAHalf]

SLYDAWG is good with a Holley carb

[turbo2256b]

ok, I'll adjust that screw if I can get to it.
thanx

You usually have to use a wrench to get at it.

It is also common to find that real accurate adjustment of the choke system is best done in cold weather. If it takes a long time to warm up its addjusted too far closed for abeniet temps. The black cap on the side adjusts the spring tension. Tighter takees longer to heat up closes the choke blade.... the spring looser quicker opens the choke blade.


There must be a speed shop near you most carry the Holley tuning book by HP.
This thread could get verry confusing without it.
There are a lot of circutry in a carb THAT COULD NEED MODIFIED. Idle Transfer slot / throttle blade relationship, how to realy adjust idle speed, Idle Feed fuel restrictions and there positions how to modify, idle and main air bleeds and modification, main jetting, emulson tubes, power valve selection, secondary timing spring selection, accelerator pump sizing and cam selection for drag and or street. Power valve restriction sizing.

Before you get into all this timing must be dialed in to get all the carb stuff right.

[Pirate]

so, I got a Holley 4160 Carb on my MAGNA 302X...and being that I'm 21, I dont know anything about tuning carbs.

its got an electric choke and vaccuum secondaries.



so, right now the biggest problem it is giving me is a super high idle...I pump it one small time and fire it up...turns on and revs to 2K...so I tap the gas and it go down to like 1800-2K...
I've turned that hockey puck looking thingy all the way lean(clockwise) and it doesnt make a lick of difference...the fast idle has gone down to more like 1600 when I tap the gas, but that's it.
I dont mind a fast idle, I just dont want it to get above 1600rpm...and it takes forever to warm up the choke...anything I can do about this?

oh, on a side note, I'm starting to get a little bit of popping when I accellerate....timing?

EDIT: I didn't see the rest of the replies above this one...sorry....

There is a choke/idle adjustment screw is part of the choke linkage behind the choke thermostat (hockey puck). It is the little gold screw to the right of the picture above. That's what adjusts choke idle speed.

If there isn't 12 volts (ignition sourced, if you hook it straight to the battery, the choke thermostat is on 24/7, and will eventually burn the car to the ground, or burn out the thermostat), if there isn't 12 volts hooked up to the choke, it won't work, and you will constantly have a high idle. That taken care of....


Popping: One of the following.....
1. Does it do it while trying only to accelerate? Accelerator pump problem....if the accelerator pump is shooting gas, you might need to swap in an accelerator pump ramp (look on the left side of the carb above, where the gold accelerator pump fulcrum arm goes to the carb throttle shaft, there is a plastic piece in there that you can change to alter accelerator pump ramp rates.

2. Does it pop while under steady load going up a hill? Provided timing is correct, the primary jets (front of the carb) are probably a few sizes too small. When doing this, increase jet sizes in two-number increments.....I am thinking it should be using around a Holley 68 jet to start, depending on which motor is in there right now, and whether or not you are forced to use oxygenated gas.....which leans out the fuel mixture.

[turbo2256b]

Easyiest to take it to Gerry and pay him a few bucks at least enough tuning to keep you out of trouble with the engine

[Mr. Land Yacht]

I would go to him but I cant go yet...is isnt broken in yet so I cant drive hwy to get to him.

I know it has a new accelerator pump in it, that was in the rebuild kit.

[phayzer5]

He ain't - his fast idle is set way too high, and fast idle is engaged when the choke is - he gots electric choke so when he starts cold his choke is engaged, whether he wants it or not. Also I disagree with Justin's idea of wiring choke wide open - MI ain't no FL, tis pretty darn cold in the mornings, and Colin uses his car to get to and from work.

I didnt say permanantly, only to help simplify things. It may not even be the choke thats your problem...you could have a base problem that the choke just adds to since it is designed to run the engine a bit faster to warm it up.

Trust me, I know how cold Michigan can get. Most of my family lives in the Marquette/Negaunee area, and I spent a few years there growing up climbing the 10 ft snow drifts in my front yard to get to the bus stop