Holley Carb Troubleshooting and Rebuild - Things to Check!

[uhfnutbar1]

Holley is one of the simplest and best design but your to stupit to know that

[Nitro888888888888888]

fuel level should be at the bottom of the sight plug

[billybb17]

I have the exact same problem with my Ford Carb on a 66 ltd 352 cu in. I'd like to try to rebuild it but am too intimidated with the procedure

[skatepunkzero]

SRV!!!!

[71bee383]

the Holley 4160 is ALWAYS gonna be a problem. if you must use a Holley, definitely go with the 4150 (double pumper) with the center hung floats.

I personally prefer using the Edelbrock Thunder series AVS. great power, easy to tune & no problems.

[herbiesnerd]

Sounds like you were right on track with all your diagnosis. Holley has great videos demonstrating all the troubleshooting and tuning techniques. As far as jet size, the best way to test for the proper size is start with new spark plugs. Take the vehicle for a hard wide open throttle spin down the road and shut it off immediately. Pull the plugs and read the color. You want a nice light chocolate brown color for the perfect mix. Holleys are easy to change out the jets. Never drill them out.

[wakawu]

same problem here thanks for the vid. bottomed the air mixture screw all the way then to 1/2 to 1 turn out and it was still flooding the spark plugs. i only managed to start it 1/2 the time. i'm getting ready to rebuild it altogether

[Cutlass81383]

I HAVE A 750 HOLLY AND MY CAR BREAK UP A LIL WHEN I GO DOWN THE ROAD. I THINK I NEED TO GET A SET AGAIN. I JUST GOT THE THING REBUILD JANUARY OF 2010. SMART GUY TO KNOW ALL THE RIGHT NUMBERS FOR EVERYTHING I WASH I KNOW WHAT SHOULD BE WHAT BY THE NUMBERS

[AllThingzVideo]

@Cutlass81383 Dont be too quick to blame the carb. So may other factors effect driveability. Intake leaks (sucking air); Fouled plugs; Timing set incorrectly; Timing advance not functioning correctly; Bad wires (shorting to block); Stuck valve(s); Worn cam lobe; Cracked dist cap; Burnt rotor; Loose timing chain; plugged PCV valve and so on. A good vacuum gauge, basic tools, and a Children manual are good troubleshooting tools.

[screwopenborders]

I have a 64 t-bird 2barrel that will run really good for a bit then die, it seems like the oil got really black quickly. The battery seems to be dead after 20-30 mins so I'm going to replace the alternator.

[AllThingzVideo]

@screwopenborders Oil will get contaminated quickly if your PCV valve is not working or clogged. Excess piston backpressure will build up in the crankcase and the exhaust blowby gases will mix with the oil. If severe enough, this can also cause the engine to stall. Replace the PCV valve or spray it out with carb cleaner. Shake it with it out of the intake and you should feel and hear the ball rattle inside.

[screwopenborders]

@AllThingzVideo Thanks. Is the PCV valve around the carb?

[AllThingzVideo]

@screwopenborders The valve should be located in the intake near the carb. However, based on the engine year, it might be located in the valve covers as vents? Look for a large diameter hose, about 1/2", coming out of the carb and follow it. The other end should connect to the valve. The valve is about 1/2" in diameter and about 2 " long with nipple fittings on each end. If there is no valve, then the crankcase pressure is being relieved thru the valve covers. Make sure those ports are clear.

[grngs1]

Thats a small carb for 400 cu.in. I have a 750 on my 350, and it fuckin rocks!!

[Mopardude]

Thats a cool idea for a work surface!

[NinjaNeglector]

get rid of that holley pos and put an edelbrock on it you'll be glad ya did!

[kamphwagon1]

@NinjaNeglector If those edelbrock carbs were so good how come NASCAR racers don't use them?........Edelbrock makes a good intake manifold but that carb is nothing but a old carter AVS a shity carb to tune ,Holley is the easyest to set float levels, make jet changes with the most versitility in tuneing options period the reason it's the racers choice !

[ACHEESEDANISH00]

Nice i got a 72 firebird

[OldWrench45]

You might want to check the main body of the carb to see if it's warped. With float bowls and metering bodies off check the surface of the carb body with a straightedge. If the main body gasket surface isn't flat gas can be sucked directly out of the float bowl into the intake manifolfd causing a "rich" fuel mixture. I've saved dozens of Holley's that people junked because they couldn't "fix" the rich condition. Simply take a flat file and carefully file the main body gasket surface flat.

[Simpdine24]

my holly double pump four barrel bogs and shuts down after i floor it i was thinking bad jets or something can u give some advice....

[AllThingzVideo]

@Simpdine24 That can be caused by a bad accelerator pump (ripped diaphragm); the wrong cam on the linkage; main jets too small (squirter's); timing not set correctly; manifold vacuum leak; insufficient fuel flow or pressure (clogged filter); and on and on. You have to step by step change one thing at a time. I would start with timing, idle mixture using a vac gauge, float levels & fuel supply, then check for vacuum leaks.

[kamphwagon1]

@Simpdine24 Shuting down sounds like a fuel delivery problem ,not that other problems may exist, boging can be caused by inadquate fuel delivery, but also a improperly sized carb to engine size, to big for the engine ,transmission ,rear axel ratio and vehicle weight combination . the preformance potental of the engine also comes into play as it dictates volumetric effecency ,a stock 350 chevy only has a 80% effecency, Holley has a website and will E mail the formula for choseing a proper carb.

[Chevymen350SS]

yes the vacume advance on the distributer. it hooked up rite but it is adjustable. how will i know if the vacume advance is set correctly. timming on the engine is correct.

[383snowman]

what would a holley 6711 double pumper be 600 650 750 etc

[AllThingzVideo]

@383snowman That's a 650 DP

[Chevymen350SS]

i just installed a new vacuume advance on my chevy 350, 600 CFM Vac. 2nd holley carb. and how can i tell if the vacuume advance is set correctly? any info will greatly be appropriated. (Dont have a vacuume gauge)

[AllThingzVideo]

@Chevymen350SS A vacuum advance? You mean the advance in the distributer? Vacuum advance only applies after timing is set (with it unhooked) The vac hose should be connected to the metered vacuum port on the carb above the idle mixture screw. If this is not what you are referring to just let me know. Thanks

[1966nova2]

i tried another carb on my 327 v8 still backfires threw the carb at temp can any one tell me whats up i even backed a 1/4 turn lose on all rocker arms but it still does the same thing no change???????? help

[AllThingzVideo]

@1966nova2 I would first check the timing, with a light. Set valve lash where it needs to be. Double check the spark plug wires are on correct plugs. Is the distributer cap and rotor new? Is the engine built or stock? What recent work have you done to the engine? Does it backfire when you attempt WOT or just at idle or both? What is your experience level with working with engines? Do you own a vacuum gauge?

[PINKFLOYD7465]

@1966nova2 Sounds like the timing

[MISTYBOUDREAUX]

dude you may have saved the fate of my carb. i instaled a trick kit on mine as well, and also some new brass floats, but the back feul bowl stayed either flooded or dry. so in a rage i maxed out the needle in respons to the high feul levels. i have given up hope until now, but with this new found info i with once agean rip out that damn holley and kick its ass and either make it work or turn it into a useles pile of smashed metal.

[chargertank]

Buy a DEMON!!!!!! #1 carb!!!

[71bee383]

1) Toss those nasty floats & get some good brass ones. replace the needles & seats. I had the same issues with an old 4160.

2) Vacuum operated Holley's are HORRIBLE when you have even the slightest air leak from the carb, intake, or carb to intake gasket. ALWAYS use a vacuum gauge when tuning your Holley.

3) Toss that pile-o-shit & replace it with a good ol' Carter AFB or AVS.

[AllThingzVideo]

@71bee383 All good points. Im actually swapping out the cam as we speak and will post a tear-down vid shortly. Going bigger on the cam and installed timing gears instead of chain. Im hoping the damn carb will be big enough for the new flow demand. If not, Im dumping it for an Edlebrock with no choke plate and dual inlet. Im tired of efing with this carb! Haha

[71bee383]

@AllThingzVideo You'll definitely be a helluvalot happier. Holley's are great carbs for running down the track...that's about it. if your Poncho 400 is basically stock, do yourself a huge favor & snag a nice Edelbrock Thunder Series 650 CFM AVS carb. also, those Thunder Series carbs will give any Holley a run for it's money. plus, they are far easier to tune, run EXCELLENT on any street machine & the reliabilty is 2nd to none.

[RATRODTV]

Very funny comments about the number of parts.

[DMB15246]

my comment would be to get a new carb and quit messing with junk

[stevenspimpin420]

my carburetor sometimes backfires hesitates to accelerate from stop and eventually wont start back up after its been warmed up and running until i let it set for a while. any ideas on what it is

[AllThingzVideo]

Backfires can be caused by a blown power valve, or incorrect timing. If it eventually wont start my guess is it is flooding out which again could be the power valve or a stuck float. You need to get a vacuum gauge and set your idle mixture for max vacuum and then set your float levels using the sight holes. If it still does it then disassemble it and check the power valve like I did in the video. Are you getting smoke out the exhaust? Does it smell rich?

[stevenspimpin420]

i was thinkin maybe the accelerator pump because it hesitates to accelerate from a complete stop and when i driving it will be accelerating fine then it will quit accelerating and if i keep on the gas it kills it and if i let off it goes back to idle. eventually after driving down the road and repeating this process it wont start or run at all until it sets for a bit

[stevenspimpin420]

i think it is flooding but only after i keep starting it back up cuz it dies i get white smoke which i think is from the valve cover gaskets leakin a little oil.

[AllThingzVideo]

Its not the acc pump. This sounds like a major vacuum leak problem, could be leaking intake gaskets. Could also be a pinched gas line or plugged filter. Your not getting enough gas under load which also could be a wrong size power valve. White smoke is usually water or anti-freeze, blue smoke is too much fuel. Does the exhaust smell "sweet"? You could have a blown head gasket filling the cylinders with water and fouling the mixture. Do you have video of your setup?

[greendogish]

why do we work on the damn things? i love looking inside them and wish i knew everything about just one model... but so much can go wrong.. anything goes wrong may as well rebuild it completely

[eclypse256]

thanks for the vid. had my FPR go bad and shoot my carb with a full 14psi which resulted in all sorts of chaos. this was a good little primer for things i should look out for while i have it apart.

[coutts1993]

How about you give a Quadrajet a shot? They dont blow the diaphram out like a holley. :-)

[AllThingzVideo]

I had one on it but had to use an adapter plate to install it. It was already too high for hood clearance. The Quadrajet worked great actually but again, hood clearance was the issue.

I am still considering swapping for a TA setup but I want to keep it Formula original. I believe there are some aftermarket low pro air cleaner setups avail now. That may be the answer.

[coutts1993]

Believe it or not, but the factory w-72 manifold and a quadrajet do have enough hood clearance for you. there was an article in high performance pontiac about the stock pontiac manifold being the best choice! It gives you both originality and power!!!

[UnsettledParadox]

thanks for the vid. i linked it to a buddy who is too far away for me to show him this stuff on his holley

[TheGeno]

Hey man - i'm running a 390CFM Holley 4160 on an old M20 BMW motor.

Great video. Mine sat for a few YEARS with nasty gas so it needed a complete rebuild and now i'm coming to think i may have the same problem as you with the needles sitting entirely too high. Lemme know how everything goes with your carb and i'll do the same after this weekend

[BigBlockHead1]

I've the same carb on my 460 but its an 1850-3. I made the mistake o buying the NAPA Auto holley rebuild kit and didn't get half the crap i wish it would have came with. Nice car by the way....

[vidchic18]

thanks u helped me and my holley out big time!!!

[AllThingzVideo]

Hey your welcome! What model do you have and how did my video help you? I am just curious because the video was never meant as an instructional video. I was merely sharing my experience with my carb and the problems I found with it. BTW...the car is still running GREAT with the recent rebuild. I will post new vids soon! thanks again!

[pbrmotorsports]

DO NOT BENT THAT TAB..Your needle and seat are stuck ..very common...And you can use a screw driver to remove those bolts on the rear plate.I ground down an old screwdriver on a bench grinder.Coat the new gaskets with vasoline so you will not damage them in the future...leave the vacuum secondary pot on that carb. They rarely go bad and you will cause more problems taking it apart.

[AllThingzVideo]

Hey thanks for the input. I did actually have to bend the tab...the needles are now new from the kit and the float would go to the top of the bowl and still just barely touch the needle. I adjusted the level after install & seems fine. I did use a screwdriver on the back screws but did not use vasoline on re-assembly. Left the vaccum sec intact. Its runs great but still stumbles pulling hard in third almost like a misfire..it smooths out if I back out of the pedal..insufficient fuel supply? Thx!

[caballo9871]

thanks for the info.

[rink741415]

wait a minute.. powervalve 10-ish will open later than the 6-ish one, won't it? I mean: more "Hg it pulls up, the more vacuum it has.

[AllThingzVideo]

Remember, vacuum keeps the valve CLOSED, the spring on the other side pushes it open.

As engine RPM increases, manifold vacuum decreases so a 10 would open sooner than a 6.

Avg idle vacuum on a stock engine is 18 to 20. As you accelerate, the vacuum drops...you would reach 10 before you reach 6. Picture the needle on the gauge dropping from 20 to 5. Built engines idle vacuum at 12 or less needing a smaller valve like a 6 or 4.5.

Hope this helps explain a little. PM me if you need to.

Thanks

[rink741415]

oh yeah.. :). engine vacuum works the other way around.

[chevykicksass505]

You gave me some great tips on things to check whether you meant to or not. power valve, floats etc. i just installed a 650 mechanical double pumper on my 350 and i got it running but it DOES hesitate when i give it some gas. any ideas? thanks in advance

[AllThingzVideo]

Accelerator pump could be weak or have a torn diaphragm. Look into carb with engine of and give throttle a quick pump. Fuel should squirt out the nozzles in a steady stream. Also, the primary squirter jets could be too small, or too big. Each condition would cause too lean or too rich. Many factors contribute and its hard to cover all in a comment. Send me a PM with your recent tests. I will help where I can. Thanks

[schoolmaster1945]

A classic "Holley Leaker"...lol...