Thread: Holley 4160 Carb tuning

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I bought my 67 Galaxie XL convertible roughly a year ago. Right off the bat, there were problems the prior owner either wasn't aware of, or declined to divulge.

As this is my first "project" car, it's the car I'm also learning on. Due to a stalling problem, I started haphazardly adjusting the carb. Ultimately, it turned out to be a tank/sending unit problem. That problem is now fixed, however now I'm dealing with potential out-of-adjustment issues.

Here's the carb:



I've done several things to the carb in the course of my aimless adjusting.

1) Disassembled & re-assembled the secondary pump
2) adjusted, un-adjusted, and re-adjusted the idle mixture screws (the two screws on either side of the primary fuel bowl)
3) adjusted & re-adjusted the fast idle screw (the one that artificially pulls or releases the throttle linkage).
4) I've unscrewed, then rapidly re-screwed the fuel metering access bolt (on top of the fuel bowl) while the car was running. That was a nice surprise.
5) Checked the fuel bowl level through the site plug. It's good.
6) Discovered three cracked vacuum nipple caps.

Now, the problems, as I see them.

1) The car hesitates something fierce when heavy throttle is applied from a stop, almost to the point of stalling it if I don't back off a little.
2) My exhaust is FULL of black soot (or was, until I turned down the mixture a little). You could cup your hand in front of the tailpipe, and smell a strong odor of gasoline.
3) After believing a rich mixture, I turned the screws in a bit. Then I was having problems with the car stalling at idle, so I turned the fast idle out a bit.

All in all, I think a tune from "zero" is necessary at this point. Probably easier for me as well.



Thoughts (other than box that thing up and send it to someone who knows what they're doing. )?

some of the problem dosent sound like just the carb out of tune some of your problems sound like a timing issue. get a timing light and make sure the motor is in time because there is no sense in tuning a carb on a motor that isnt timed. on the side of the fuel bowls there are screws on the side adjust the fuel level until it is level with that hole im pretty sure you adjust it from the top (not completely sure havent done it in like a year) im only learning about carbs so i hope someone can explain what im saying better i dont know all of the names of the bolts and screws adjusting the idle should be easy its right by the throttle also i would buy a rebuild kit. i have a fresh rebuild 4160 that i will sell for like $35-40 i have never had it on a car since the rebuild so its not tuned at all if you are interested you can email me at
tyler.brown@lakeviewacademy.com
like i said im not a carb expert but my dad is pretty good with them if you could get a owners manual for the 4160 im pretty sure it tells you everything you need to know to tune it

Well, I bought the Haynes for Holley carbs, but it seems to really only focus on disassembly and reassembly.

While the price on the 4160 you have is attractive, I already have one I can't tune. I don't need two. :P

well this sounds like it could be more than a carb problem. it sounds like you could benefit from having the heads reworked. and new rings.

Black soot indicates an overly rich condition on the carb. The bog on acceleration would indicate the secondaries are opeing too soon, this is adjusted by changing the spring in the vaccuum chamber for the secondaries. The idle problem could be a vaccuum leak, check for that with a spray can of carb cleaner. Spray small squirts of it around the carb base, and all the other sources of possible leaks. There's a lot of good books available on tuning Holley carbs that are far better than a Haynes rag.

The idle mix screws should be set about 1 1/4 turns out from lightly seated. After that adjust each the same to achieve the highest idle or vacuum . Then go back and adjust the idle speed screw down. This is best down in reverse with a trusted friend on the brakes and the parking brake set. You can adust the idle mix screws once more to get the highest idle then readjust the speed screw. look at the sight plug, is the fuel level still just below middle? It should be. If its high you may still get black smoke at idle at times. I like to set mine a little low an worry about running out of fuel at the top end later. Regarding the bog, it can be the accelerator pump or the secondaries opening too early. Either put a stiffer spring in or wire the sec shut. If the bog still occurs its the pump. A black cloud when you hammer it means too much fuel. Either the wrong cam or the wrong shooters. get a book, I have
" how to tune & modify carburetor performance" by motorbooks int and it has saved me many times on all kinds of carbs. If you lose the bog with a stiffer spring or secondaries wired shut, the spring you have is too loose and needs to be stiffer. Too stiff will give you a flat feeling. then you play around from there. your parts store or a place like summit will sell you an assortment pack of color coded springs that will take care of the vac sec. Otherwise, the pump cams are color coded too, an you can buy a kit or seperate