Holley 4150 carb adjustments

[gert]

Anybody a Holley person on here? I have personally always preferred Carters over Holleys but I now have one on my Jeep that's in really good shape. I am still getting a rich idle(12 to 1) with 20 plus inches of vacuum. I have the throttle blades pretty much all the way closed and idle needles pretty close to all the way in. Its a 650cfm 4160 side float model and IIRC I have #62 jets in the primaries.

It has an aditional issue that as it is under load and the vacuum drops to 15 inches or less on part throttle it will lean out to 15 to 1 or more which is confusing to me.

I have a really slick Percy's adjustable jet on the way to adjust the jet sizing without ever removing the fuel bowls or draining fuel to help with the tuning

I am wondering first of all if i change to a #60 jet if it will lean out my idle?

is a #62/60 normal for a stock 360 V8?

If I drill 3/32 holes in throttle blades will this lean out carb at idle? why would i need to on stock carb/motor?

Any advice you can shed or links to knowledge you can provide would be awesome thanks

 

[gert]

Ok I got some head way on this, unfortunately I’m out of time for today as I have some family commitments to attend to,

I was reading thru my super old Haynes Holley book and it suggested to crack the secondary throttle blades alittle so I shoved a feeler gage under the blade stop and that leaned the carb out to roughly 14.5/15 to 1, I’m out of time to get it adjusted right today since every adjustment on a Holley seems to be engineered to be a pain in the butt but I will get there



The adjustment screw is in the throttle plate only accessible while off the motor go figure


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[RiverandSand]

What is the list number, I can look it up in my holley book and give you the specs for out of the box (baseline). Changing the idle screw setting for the secondary butterflies is the preferred method over drilling. Drilling is usually done when the cam has a large overlap and Hgs are low @ idle. Also check your power valve 6.5 is usually used in fairly stock engines with higher Hgs @ idle.
Before EFI, Holleys carbs were the staple for HP cars and trucks, tuning them is becoming a dying art. Even NASCAR is using EFI these days.

 

[gert]

What is the list number, I can look it up in my holley book and give you the specs for out of the box (baseline). Changing the idle screw setting for the secondary butterflies is the preferred method over drilling. Drilling is usually done when the cam has a large overlap and Hgs are low @ idle. Also check your power valve 6.5 is usually used in fairly stock engines with higher Hgs @ idle.

Before EFI, Holleys carbs were the staple for HP cars and trucks, tuning them is becoming a dying art. Even NASCAR is using EFI these days.

I will be able to get the list number when I get home, I rebuilt the carb and put at least a 6.5 maybe higher I will see what it is when I put the Percy adjust a jet in

I red somewhere that you want to take your idle vacuum at divide by 2 to get your power valve number that would be like 9.5 for me, any reason to go lower?


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[gert]

Well I finally got a chance to work on carb today, got lost in Dallas trying to return the other block, Holy cow I could max out several credit cards walking through the Summit Racing store

So I had #64 jets in primary and a 6.5 power valve




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[RiverandSand]

Summit racing store is awesome, we go to the Sparks store during Hot August nights. I could spend all day in there.
The 80457 has 3 versions, all were 4160s - 600 cfm. The jets and power valve you have installed are stock. Has adding the new block helped? What are the jet size in the secondary? I would adjust the both sets of butterflies to the same setting, then go from there. What are the spark plugs look like, should be a light tan if tuned correctly.

 

[JimsCJ5]

Cracking the secondarys open a little more is an old school way of getting rid of the typical Holley richness at idle. I tried that but wasn't impressed and went back to stock settings. The adjustment screw can be replaced with a hex bolt so it can be adjusted on the vehicle but it's still a PITA.
Check your fast idle and choke linkage and make sure it is not hanging up. Holley has a pretty helpful tech department you can call or email.
Good luck

 

[gert]

Summit racing store is awesome, we go to the Sparks store during Hot August nights. I could spend all day in there.
The 80457 has 3 versions, all were 4160s - 600 cfm. The jets and power valve you have installed are stock. Has adding the new block helped? What are the jet size in the secondary? I would adjust the both sets of butterflies to the same setting, then go from there. What are the spark plugs look like, should be a light tan if tuned correctly.

I bought this carb off a member here, and added the secondary metering block to be able to adjust the secondary jetting.

I am going to add more gas in the gas tank when i get home but it defiantly is leaner now so thats a good start

i will have more to report this afternoon when i get home, i am going to check plugs and timing as well

 

[gert]

Cracking the secondarys open a little more is an old school way of getting rid of the typical Holley richness at idle. I tried that but wasn't impressed and went back to stock settings. The adjustment screw can be replaced with a hex bolt so it can be adjusted on the vehicle but it's still a PITA.
Check your fast idle and choke linkage and make sure it is not hanging up. Holley has a pretty helpful tech department you can call or email.
Good luck

lol must be old school, read that trick in my Haynes Holley paper back book

I think i am going to toss the whole choke assembly in a box because its not hooked up and has been cranking and running great without it

 

[RiverandSand]

I bought this carb off a member here, and added the secondary metering block to be able to adjust the secondary jetting.

I am going to add more gas in the gas tank when i get home but it defiantly is leaner now so thats a good start

i will have more to report this afternoon when i get home, i am going to check plugs and timing as well

Ok cool, I was wondering about the secondary block, but it's a good mod, more adjustments for the secondaries better than messing with a plate.
If you flip over the carb and look into primaries you will see a small hole an a slot, the slot is the idle transfer, the butterflies should expose .045 to .060 inch of the slot. The hole is controlled by the idle screws. If the idle screws don't really have an effect idle you have too much of the slot exposed.

Messing with carbs is all old school these days.

 

[gert]

Lol I feel old fiddling with a Holley now, the adjust a jet makes jet changes to easy lol

I have it idling at 15 to 1 at a pretty low rpm, have to get a working tach to find out what the number is

Driving afr is anywhere from 15 to 1 to 13 to 1 so I will start looking at accelerator pump shot adjustments nest I think and try to dial in the main jet size

Had to stop and measure for rear shocks so I can order them. Found the 6 inch lift shocks work for my Jeep so I have some ranchos on order


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