Holley carb flooding & hard starting solutions

a quick video on some different flooding situations and how to fix them.
order check
FLOAT LEVEL
FUEL PRESSURE 5 TO 6 PSI
NEEDLE AND SEAT CLEAN
CARB HEAT - SPACER MAY BE REQUIRED
THE FLOAT ITSELF
OTHER FACTORS- the damned carb is way too big or is dirty inside.

[@vigt548]

This guy is a genius. Every one of his videos is phenomenal.

[@jwolverinepunchkicker1621]

Best explanation and walk through I've found in a long time. Thank you so much for your video. Sincerely, John Randolph

[@wvangus82]

Thunderhead, thanks for the video bro! I just wanted to add this. When my 1850 (600 cfm vac.sec.) was flooding after shut-down, I tried everything. It had been freshly rebuilt with new needles, power valve, gaskets, etc. and had been flooding after shut down since I put the carb on the car. I bought a fuel pressure gauge, running 3 lbs of pressure. So, after pulling my hair out for a couple months, I finally changed the needle on the secondary side, because the leak always came from the sec side. The new needle fixed the problem even though the old one was a month old with ABSOLUTELY NO visible problems. I also had this happen before from one of my eyelashes getting in a needle valve during a rebuild lol.

[@evrenerdogan2890]

good point thanks

[@BayLuv87]

dumpster diver daaaam an eyelash lol....shows how sensitive these parts are

[@55chevyman4u2nv]

This really help my 350 chevy in my 55 Chevy very hard after warm up I replaced the O ring and add 11/2 inch spacer no more problems I thank you this helped

[@ThunderHead289]

i have used the n271+ comp cam twice and was very pleased with it. its a solid lifter cam. with poly locks you never have to adjust it as it never loses lash with the locks. imo, much better than hydraulic. if you car is an automatic, then id stick with something very stock and look into heads. higher compression and higher flow is where many ponies are gained. and with a smaller grind cam, it would be very torque for the street. . .

[@thekingsilverado3266]

I wanted to get my 2 cents worth of advice in here with you folks. First of all NOW DAYS WHEN YA BUY A BRAND NEW HOLLEY LIKE I DID BRAND SPANKING NEW IN THE BOX. THE FLOATS ARE NOT ADJUSTED THEY R ALL OUT OF WHACK SO IF U START YOUR RIDE UP AND DO NOT TAKE THE NEW CARB APART WHICH YOU MAY HAVE TO IF THE SIGHT GLASS AREA ENDS UP FACING THE FIREWALL AREA OF YOUR VEHICLE LIKE WHAT HAPPENED TO MY FORD OFFENHAUSER CARB CONVERSION THE HOLLEY QUICK FUEL CARB I PICKED HAS THE FLOAT SIGHT GLASSES END UPS WHERE YA CAN'T SEE SHEET. THE HINT IS HESITATION WHEN YA START IT UP THE CARB MAY NOT FLOOD IMMEDIATELY IN FACT MY TRUCK RAN ABOUT 250 MILES BEFORE I SMELLED GAS AND KNEW THERE WAS A PROBLEM. SURE ENOUGH THE FLOATS WERE WAY OUTTA WHACK NOWHERE NEAR EVEN CLOSE TO ADJUSTED. So if you buy a new Holley especially a quick fuel product make sure ya take it apart on the bench set the float levels. My advice is its so simple I might be able to teach Joe Bite me that he couldn't even mess it up. Just make sure the float tangs closes the needle seats. If U R not happy at least you know you are in the ball park and if you are a really anal old jackass like me you can actually buy a float gauge and learn how to use that to measure the floats. But us old timers don't really need stuff like that the Holley is that simple. Even to rebuild. I have Holley carbs that are now 40 years old and they still work fine. 2 went back to Holley for shaft seals and bushings and one came back brand new. Holley claimed they lost the carb I sent em. That was back when you could send Holley a carb to repair it. I don't know if ya can still do that but boy was I pissed off seeing gas leaking all over my brand new engine and $400 Offenhauser intake manifold...

[@gruntohseven5803]

Great vid.Sorry to hear about your hand.I been watching for a while and never noticed you only had one hand.

[@brkooduh66]

10 year old video saves my bacon... parked my car hot and the fuel must've been boiling andthen evapped out of the bowl. couple days after cab was flooding like crazy. this vid clued me onto discovering float and needle was stuck down from being hot and empty. thanks man i had it happen once on a car that sat for many years, didn't think it could happen in a couple of days

[@seangermanowski6396]

Probably one of the best explainations on fuel bowl adjustments and its effects on this topic . Thank you!

[@johnmiller-in5bt]

you kidding? lol.. he acted like he wasnt even sure if you went clockwise to raise or lower the float..lol

[@ThunderHead289]

that is quite doubtful as the intake charge does not hold a large enough amount of fuel to sustain a fire. id make sure nothing is spraying out of the carb, but I believe there must have been some combustible fluids in that area, like possibly oil or fuel. its hard to tell without seeing it myself, but id imagine there could be a fuel leak of some sort. you might have to run it again, or have a buddy turn it over while it runs, so when you locate the source, he can shut her down quickly.

[@hunterdeer]

I found that if the secondary continues to flood you can add a fuel filter with two outlets, run one to the carb. and one back to the return line to the fuel tank, I think this reduces the fuel pressure enough to provide enough fuel to the carb. but not blow by the needle valve. Hopefully you already have a fuel return line.

[@stevephillips2685]

Good video. Turning the float screw down will make more fuel come out of the inspection hole. Turning it up or counterclockwise will make float ride higher thus shutting fuel off sooner and less fuel come out or none at all of side hole.

[@hauntbuildersofbuckeye3866]

Thank you 😀 exactly was my problem. Your the man. Keep up the great videos😊

[@robertoleeva985]

Man.. Grrat vid.. my carburetor is doing the exact same thing.. Gonna check it out

[@fanoffreedom3003]

The problem i have is my engine was sitting for 7-8 months in a wet cold environment , its a 351 cleveland modified in a 1991 ford fairmont ghia,i put a little bit of feul in it on top of 7-8 month old feul, then poured some down the carburettor , this normally starts the engine after it sits for almost a year , but it was cranking over well but not even trying to fire, then i noticed water dripping from the rail of the 600 holley vacuum secondary carburetor, i let water out of the bowls and sight plugs about a couple tables spoons of watery as feul came out , the rear bowl was over full, the front wasnt, feul is coming up to the filter, it is not running the cars factiry feul pump as its not strong enough it cant supply the engine with enough feul and the engine stops, its running off the engines feul pump, i really need this engine to start so i cant drive to my new home because ive been evicted on short notice i have to move this car very soon a couple of days, anyone mechanically minded please help me

[@brvLdez74]

Great video! Great explanation of adjustment how to, and diagnosing flooding issues. Thanks for the video, watching it very likely saved my engine. Thank you!!

[@willyjilly9684]

Two birds one stone for me watching this video. I'm running 7.5 PSI on a Holley fuel pressure regulator and I'm pretty sure it's worn my seat assembly overtime because it floods out even (even after I set fuel level perfect, usually doesn't flood until the next day I start it). Also my fuel pressure drops from 7.5 to 4 psi after 15 mins of engine running.. not sure if that has anything to do with my flooding issue ?? Thanks

[@chancellor9677]

Dude this is awesome. Just built a 56 cheverolet patina truck. Great info on heat exchange and what will happen considering blow by. Did not know the seats could be blown after specified PSI. Awesome. Just a badass. Totally solved my problem of boil over and loosing fuel pressure mid drive from rear seat not being sat the FK down. 11 YRS later. !! Thanks.

[@forestlawrencegrading9154]

The next Holley video that you do you should warn about a dry carburetor that's in a box being shook around upside down it can cause the needle beneath the squirters to get stuck up in the that's the check valve for the accelerator pumps I'm selling this one from experience LOL

[@coreyreynolds9239]

Do u have any videos of why a Holley would have late throttle response?

[@brianworley7705]

I know this video has been out a while. I can see a couple of possibilities of causing our fuel out the vent. Say one's float sank due to boiling from overheated intake. What is the recovery steps? Will the float actually float again? What next, rebuild? Holley 2 barrel in our case.

[@spdlsz]

im not getting gas in my front bowl. ive adjusted the needle and seat up and down and changed it still no gas. checked the float it doesn't have gas inside it. no pressure regulator and mechanical pump thats only a few months old. the back bowl always works as it should

[@ThunderHead289]

Check to see if it has one of those filters in the bowl inlet, also, look up at the needle and seat when you have your bowl off and see if it actually moves up and down with the float.

[@GaryH-pw9cm]

I had a Holley 600 on a light weight hotrod with disc brakes that could stop very quick. Could not figure out why if I hit the brakes hard the engine would stall out. Seems the rear vent pipe would shoot fuel out into the venturis and stall the engine. Put a hose on the vent pipe that went up into the air cleaner and never had any more problems.

[@saneauto]

I was gonna make this video for my nephew but now I dont have to. Thanks Ill be sharing it to his FB.

[@-s442]

Hey man, this does help out a lot. i having the same thing happen to my mustang and trying to get it fix.

[@R1FamilyR1]

Bump your idle up. You know everytime I get a new old car I rebuild the carb. Reset everything to spec and tune with a vacuum gauge from there. Between that and timing, changing plugs and setting valve lash, by the end you get really close to the classic and your shit it's usually running wide open contemplating a cam change on the accelerator pump and lowering your power valve, ... Sweet video

[@scottawes3217]

this carb has been such a dick in my jetboat. got a typical 460 with 429 heads and this holley has ruined the day more than once. I hate the pic of shit

[@SuperInline6]

Clogged high speed air bleeds are another caus of flooding on holleys.

[@blackicethehusky5894]

I have a 1985 Ford F-150 we had fixed everything under the hood except the carb… the summer time ran perfectly. Recently in the month of December of 2022 it’s been not starting when you have it at normal temperature any suggestions?

[@sambrown6939]

Was having same problem this winter with my '86 with the 460. Giving my carb a quick clean and rebuild did wonders

[@FEDERALBOYSENTERTAINMENT]

Mines keeps cutting off when I put in reverse are when I put in drive

[@waynep343]

Put an 1984 corvette fuel filter before the mechanical fuel pump . It has a 10 micron element . It will stop sediment from getting into the fuel pump check valves and needle and seats.

[@TheCatOfAges]

my holley 2300 is having terrible flooding issues, i cant quite figure out why its running so horribly rich at only one turn out for the needles. should i crank my float down further than whats recommended stock? its a 1864a carb for a 383 mercury carb. around 350cfm. i have it on a 292 Y block

[@1Thanous]

I have a Holley 650 DP and my truck started to run like crap when I was light on the gas or coasting, seemed like it wanted to stall, lucky I got it home... Turn the key for the electric fuel pump and fuel was coming out of front bowl, sounds like a stuck float to me, going to go back to my old carb

[@ThunderHead289]

The float is stuck or you are running too high of fuel pressure, simple fix!

[@frankiehavocbroadnaxfranki8460]

h

[@mr_gacho]

Great Video. I got the exact carb on a 383 Super Stroker in a Impala 64SS. Big Time cold start problem. Runs great when it's warm. Any tips on cold start issue?

[@endlesssummer3406]

I'm a carburetor idiot. I've tried but get overwhelmed. I got a 87 Bronco XLT with the 351W automatic 3 speed. There is nobody in a 200 mile radius from me that rebuilds carbs. I had a guy do it 2 years ago and he did good but not 100%. Everyone tells me to just buy a new one, yeah, 400$. I'm on disability. Do you have a step by step video for tuning or should I try to rebuild or just break down and buy new? It's sending gray smoke out tailpipe and smells so rich

[@ThunderHead289]

Type in thunderhead289 tune carb to the search bar

[@KRyan4u]

Keep up the great work. Neophyte mechanics and car enthusiasts need this information. Regards, KR.

[@jakefriesenjake]

I always shut off my electric pump first, then the engine

[@lilbans]

Mine mustang runs but Somtimes won’t turn on but engine stills turns an smells like gas so I think it’s flooded when it does that Maybe when I floor it too much still drives everyday only happen sometimes an turns on with a jump .

[@redneckoleptic1813]

America HAS NO QUALITY CONTROLL nowadays!!! This young man knows already^__^ Take it with a grain of salt and maybe do a better job at your job!!! So, keep the counter comment in the trash! Thnx!

[@zombillyboogie9370]

On the last segment you were talking about if you have a mechanical pump there’s a chance that pressure can remain in the line after you shut the car off, if that’s what it’s doing how do I quickly relieve the pressure? Would holding pedal to the floor do it? And is there a better way to do it than that. And lastly how do I keep that from happening again?

[@rolando4812]

Thunderhead, I'm trying to square out this fuel issue that I'm having. After i run the engine for a bit. I stop getting a good stream of fuel coming out of the squirters on my holley 4160. I disconnected the fuel line that goes to the carb and determined that the fuel pump works fine. I'm thinking that debris has gotten into the carb causing no fuel or a very weak stream. What's the easiest way to check if anything is clogged in the carb? Let me know if you need more info. And thanks a lot for answering the questions that I post. This channel has helped alot with my truck. Thanks again

[@ThunderHead289]

Rolando Paz no problem, that is what i made it for. first i want to clarify if we are talking about the accelerator pump nozzles above the venturies or if we are talking about the venturies themselves. my first bit of advice would be to check the float bowl level when this is happening. also, check this when you first start the engine and let me know if there is a difference. i dont think it is trash in the carb because it would be having the problem with the engine warm or cool. check your accelerator pump arm and make sure that there is not any play there, but also that it is not tight against the sprung nut(front driver side of carb). when you adjust that main idle scew, it will change this geometry and it will need adjusting as well. get back to me with this info and i can go from there.

[@gplmr32]

Hey ThunderHead289, would you consider a 750 cfm Quick Fuel too big for a Ford 302 with Edelbrock Performer RPM heads, Victor Junior intake & a nitrous cam? Thanks

[@drewdowncutomz4792]

I'm stuck on mine i doing a rebuild on my truck replaced sending unit ,replaced pump ,added a fuel pressure regulator and replace the needle and adjusted but no matter what fuel blows to the top of carb??? I'm stuck

[@jackinthebox6143]

Actually, I would add the problems with the choke on these carbs. Especially the automatic choke. But also the mechanical one. They're more trouble than they're worth. Especially when you're in a hurry and you don't have 26 minutes to reach operating temperature.

[@fresh1388]

I have a 670 Holley and had a problem with the pressure staying in the line and flooding my engine. I notice this about a day later and diconected fuel right away and drained oil than pulled plugs and flush gas from top of pistons. Replaced plugs and changed oil and filter But now I'm having a problem with popping like timing is off. Any idea?

[@jackinthebox6143]

I always had that problem bombing down the motorway nice an sweet for an hour or more then we go into the service station. Switch off the engine and go in for a cup of tea. Then we go to leave and the car won't start. I'm one of those the kicks the gas to start up which is the worst thing. Just keep that foot away and it'll usually fire up on the third or fourth time.

[@johngranato2673]

Bad needle & seat O-rings are a very common problem causing, as the man says, fuel by-passing the needle and seat and flooding the engine. I wonder how many carbs have been tossed by folks who don't know these basics. Remember, Holley has been around for over 100 years. They are not hard to maintain if you take the time to learn about and look after them. Good luck!

[@johnjohn4465]

I'm a Holley Fantic !!!!! But with ALL of the " Micro Managing " These Holley carbs NEED , Should I be moving on to another Name Brand of Carb that will be More Efficent ???? John

[@SBrandon562]

Thanks a lot, I recently rebuilt my Holley and it was running great for a while but then started flooding out and left my ass stranded lastnight lol got up this morning and started checking things out and figured i'd look for ideas. This video helped solve the problem. The primary needle was seated too high and caused flooding. Thanks again!

[@deepbludude4697]

Thunderhead where are u getting the phenolic spacers at? I have a holley 2bbl on my 351M my google phoo sucks at the moment.

[@doublej118jc]

Good info! I have the hard start when engine is warmed up problem big time. My engine has about 250 miles on it and was dyno'd, but I don't think the carb was ever set up right. It starts up perfectly when cold, but after warm up and I shut it off, I see gas vapor coming from the primary side of the carb. Hopefully after I check my fuel pressure I'll find something irregular.

[@ThunderHead289]

Go to my channel and watch my carb videos in the playlist. I'd say your carb is getting too hot and boiling the fuel. Add an Insolative carb spacer

[@doublej118jc]

I have a 1/2" wood spacer between the carb and engine now.

[@ThunderHead289]

+doublej118jc possibly a vapor lock issue I wonder. Assuming mix screws and float height is correct

[@doublej118jc]

When engine runs I get a strong exhaust (rich) smell so maybe carb is out of adjustment. The dyno guy did do an adjustment and the car runs extremely well and very strong with excellent throttle response after warm up.

[@7jack7]

Although it is not specific to Holley carbs couldn't a heat riser valve that is stuck shut cause the intake manifold on V6s and V8s to overheat, which would in turn cause the fuel in the fuel bowl to boil, which would in turn flood the engine?

[@keystonecountryboy]

I see O scale track in background....

[@yamahaguy1732]

My truck starts fine on a cold start I barely turn it over and it fires but when it’s warm and I let it sit for a few mins it is hard to start I have to crank and pump a few times could this be the problem

[@jamesmangus1751]

You pressure is wrong. 5-6psi isn't much. My 351w with a Holley runs 7.5 and runs perfect

[@The_Vaporizer]

I've watched almost all of your videos and they're great but nothing has worked on the 4150 I have. It's had everything done to it just like in the videos but still my engine only starts for a few seconds and that's with carb spray. I want to believe that this thing can work but no, it never will.

[@markteague8889]

Thanks for posting! Pretty sure I've run into the same exact issues.

[@scottbearden2499]

i have a 408 stoker motor with a holly 750 it want let me lean it its acting like its flooding what could it be

[@marcol7847]

My Holley is leaking gas from the diaphragm . Any tips? Thanks !

[@dfinkieme520]

I never thought of a pinhole in the brass float on a used holley.

[@billyjack3361]

Thunderhead, I deleted the rude comment I made. Sorry. You did good.

[@ThunderHead289]

Thanks, no hard feelings man. We're all here to learn a little and have some fun at the same time

[@blakestrong2593]

you are god sent this helps I was to the point of buying a new one and I really like the one Iv got it ran good before then just started flooding out every time running been trying so hard to figure out why your awesome man !

[@hectorortega9131]

Here in the Arizona Heat i even use white hard Nylon Washers between the stud nuts and the carburetor base..

[@nuclearbum9858]

i go up down cant get fuel to come out the secondary bowl....did i break something and how do you tell if the bowl is stuck

[@PB0Y1834]

My problem is I'm running a quick fuel carb 650 4 barrel double pump..and when I'm driving and I stop at a red light, my car boggles down and dies out on it's own..is the floater or needle causing this?

[@ThunderHead289]

check your fuel pressure. i would assume that your pressure is rising from heat soak and flooding the carb out. it is in your float level adjustment which is related to your pressure. i run a regulator set to 5 psi on all my carbed vehicles for this exact problem

[@davidasherii5696]

car will start and drive but once u let off the gas pedal it floods and stalls the car out

[@steveproctor1748]

I soak my old needles and seats in CLR. It really cleans them.

[@mattshansen9814]

Very helpful video. I'm going to try that with my carb from summit.

[@Evrenthewrencher]

i used 1 inch phenolic spacer and still it ll take long time to start the car once engine is hot.but crank in second when cold.im going to try a return line

[@yungyo1088]

What kind of motor you got

[@Evrenthewrencher]

@@yungyo1088 got a 350 on my corvette. Fuel return line seems to be working good so far.i noticed engine was running hotter than it needs to be so i put a prestone flush in the radiator for 3 days 15 deggress colder already and no problem hot starting.im waiting for tomorrow to drive it around for good in the heat

[@Evrenthewrencher]

Lol i noticed i first posted my comment 2 years ago and yes im still dealing with it.finally feels like i got it this time.i removed my one inch spacer and installed holley heat shield.no difference.i isolated the fuel lines and put a bypass regulator new filters.i was gonna get electric fans as final option but may not need it so far.also wawa here in florida sells ethanol free gasoline.for 2.50 .all good

[@matthewkirkland3915]

Hey man. I apreeciate folks like you explaining things like this lol. I watched you're video but Maby you can help me with this since you didn't cover it. Everyone says to check theys things while The engine is running? What if it floods before I get it to crank? How do I diagnose which one it could be? I don't wannu just go in there and start screwing with stuff cause I might not ever get it back to where its supposed to be. And all the old guys are dieng off so no shop will work on it which leaves younge bucks like me stuck with you tube and Google lol. 71 f-100 stepside 4x4 on a bronco chassis. Mid 70's 460/c6 with a troubesum holley 650 double pumper.

[@ThunderHead289]

+swamp land well, you can check all this while its running by removing the sight plug from the side of the fuel bowl, if fuel comes pouring out, it is either flooding or the floats are set too high. you need to have constant pressure of 5-6 psi through the rpm range, and keep the heat off the fuel. (all lines off of heat sources and a spacer in between the carb and intake. heres my rig i drove to virginia and back in. kzbin.info/www/bejne/j4bQknSHpK2ana8

[@giovannikrasniqi5138]

hi i have a 350 with a mild cam with Holley 600 6.5 power valve 66 jets 17* initial timing im getting 8-10 vacuum do you think thats too low .thanks

[@ThunderHead289]

something is not right there - you should still make 14 to 15 with a mild cam id think

[@classiccorvetteguide9147]

That’s exactly my vacuum - cam is Rowdy. Almost same exact settings

[@brandoncherry1651]

You know back then I'd be wondering where the dead bodies

[@ThunderHead289]

If you are referring to me, I was an interesting character a decade ago.

[@nymuscle6691]

Thunderhead, Is it fair to say that most of these holly carbs could use a spacer because of the configuration of these carbs vs the float bowl locations ? i have a 66 ford ltd with a 390 stock manifold and ive been having problems with boiling my float bowls,recently ive adjusted my floats and its been running ok but the other day it stalled as i was standing still,just inspecting the engine bay as it was idling,i figured perhaps being no air movement being i was just idling with the hood up wasnt allowing air flow because when im driving i dont seem to have any issue with stalling,it actually runs ok at the moment,either way im gona install a spacer and see where it leads me,if you have any other suggestions id sure appreciate it,thanks for the videos they help.

[@ThunderHead289]

M .Quez hey, sorry to hear that. and yes i run spacers on everything i have. i just drove my galaxie from iowa to virginia 1400 miles and 19 hours just fine. i did have some signs that showed me my car wanted to stall when i got stuck in dc traffic. i run an o2 gauge in my car and i watched it go lean in these instances. what was happening was mild vapor lock. fuel gets so hot in the lines and it will boil in the lines into a gas form at the highest point. it doesnt help that the fuel already goes through a 180 degree mech fuel pump also. so if you understand here, at low fuel flow the fuel has a long time to heat up. what i went ahead and did was i made a fuel return line back to my gas tank very cheap. seems to work well and to of cured the issue. im making a video on my simple system once it stops raining here and il have it up and posted. stay tuned for that, you may find it interesting.

[@whittspits]

It was a circle track carb and choke disabled. It worked like a dream until I sent it with the guy and had it gone thru and he put a complete kit in it w new floats and everything. Any suggestions on good carb go to must have bible books.? It always seems like if I want something done right I have to do it myself.

[@ThunderHead289]

check the float levels first because after the carb is redone, there is no way to tell where the levels should be. make sure he put the primary jets in the correct side as well. let me know the status of those before I send you on to further things. there really isn't a holy grail of carb books that is economical to use to be honest.

[@jweb47]

I have a 69 GM car with a 350 running a stock 3310 Holley and this video hits on a topic I've been meaning to address for quite a while. I live in the Dallas area and as everyone knows, it gets quite hot in the summer in these parts. My issue is that the car uses a spot in a 2 car garage and after I park it, gas fumes are very strong. The carb is in good shape, runs strong and has no visible leaks. Also I use a stock Borg Warner mechanical fuel pump that produces (it's been a long time since I tested it but 6 PSI comes to mind...whatever it was, it was in specification) the proper flow. My initial thoughts were that the carb was too hot and as you say, boiling the fuel after shutoff since the engine temp goes up after shutdown. I haven't done anything about it yet but think I will now that your video reminded me of my problem. I hope a 1" phenolic spacer will work on my setup because I have a cowl induction air cleaner and I'm not sure if 1" will cause a problem. If you have anything to add, let me know and I'll do the same. Thanks, Joe in Texas.

[@ThunderHead289]

any type of a carb spacer is always the way to go, they work wonders on keeping the heat off the carb. one thing you could do is pull a sight plug after you have driven the vehicle but before you turn it off(have a rag below). if fuel comes out the level is too high either on account of setting or heat expansion. do not change anything till after a spacer is installed as you will require different settings then possibly. just something to think about. you can also have the air cleaner off, and when you shut the car down peer down the throat of the carb, if anything is overflowing from the boosters(common issue with heat problems) then that is most likely your smell. any other questions, just ask il do my best to respond. best of luck from iowa where its 10 degrees right now! -Luke

[@algraham1376]

I have a 4160 on a dodge demon. At idle gas drips into the secondary bbls. Briskly. It follows the shaft to which the secondary throttle plates are attached, among other things, and runs all over the manifold. Today I lowered the float level in increments a total of 4.5 turns and the condition persists. Any ideas?

[@charlespartak2435]

Did you get this issue resolved. Got a similar issue with my 283. Yesterday ran fine, went to cold start this morning and it flooded all over the intake.

[@rollerfantwo]

I just finished rebuilding my holley 750 with vac secondaries (not a double pumper). I put it back on the manifold and went to tuning the needles, floats, etc. But when I tried starting it, a fire started in the proximity of the passenger side header. Is it possible that there is raw fuel running out of the header and igniting?? Any help is appreciated...

[@frankiehavocbroadnaxfranki8460]

rollerfantwo

[@johanesivan3475]

Would this cause my idle to fluctuate a little bit? As in between 650 and 500?

[@whittspits]

I just had my 4150 rebuilt. Now it will start then die. What am I missing?

[@ThunderHead289]

check your choke adjustment first, from there I will need a little more detail to point you in the right direction. if your not opening up your choke, the engine will die. give me a running timeframe of when it dies. out driving, just warming up, and so on.

[@fastlanebruce]

Very helpful bro thanks

[@ridgerunner6008]

It was my needle valve o ring on the front bowl of my 8007

[@kevinhudson3153]

Noticed the offenhowser intake

[@davidasherii5696]

I have a Holley carb just put new regulator and regulator gauge and carb is flooding pushing from 7.5 to almost 9 psi like the carb isn't telling the regulator when it's full of fuel

[@ThunderHead289]

+David Asher II my first question is if you have an electric fuel pump - if you have a mechanical pump, I’d say the needle and seat assembly are not closing - either the o ring seal on the needle and seat assembly itself is bad, or there is trash inhibiting the needle and seat to seal

[@davidasherii5696]

it's electric pump as far as I know it is a 1989 Ford mustang 5.0

[@danw8985]

Question for you, I have a dual 650 dp setup on a raised intake manifold. Took the car out tonight and had pushed it a little hard and it seemed like I flooded my engine. My car died on idle and was real sloppy trying to drive it back. Aldo had some fuel spots on the windshield.. Fuel was all over my carb and manifold. I pulled all the brass plugs on the side of the bowls and one poured out alot. My plugs were Also pretty wet.. Any idea what would have let go on the carb? Power valve or o ring maybe??

[@danw8985]

At the moment the engine wont idle, but starts when off idle. Pretty rough though,

[@ThunderHead289]

Dan Wheeler sounds to me like a needle and seat issue. might have got some trash in it so that its not seating and now is coming out the bowl vent tube. disconnect your pump from your carb and light the engine off. have a bottle to catch the fuel. if you can then at some point get the engine to idle briefly, i would then definitely think needle and seat. i run a regulator on all my cars and i have a filter after my pump and before it as well to prevent trash from going through the system and causing problems such as this.

[@Keithhenagan]

great video. Thanks

[@Palacios29]

why my holly 4 b carb keeps shouting off?

[@leonwilliams8523]

Thanks 289 u helped me again cheers

[@alandust2188]

Great info, no so good audio. Thanks

[@nickolasrosenthal7757]

👍great video

[@alexv.100]

You use a 1", what kind of spacer?

[@1broncos7]

+ThunderHead289 This happened to me today, were my Mustang shut down as it warmed up today in Ohio. Now I have gas in my oil with no start. I'm going to replace the plugs, change the oil and filter, go down 2 jet sizes and how I don't have a washout. My pressure regulator went out on me, so now it's time for a new one. Is there anything else I should do before trying to start her back up ? I have a Summit 4 barrel 650 with and electric fuel pump. One more question. Should I shut off the pump before I shut the motor down as I think I had heat soak as the Mustang was running a little warmer than normal ?

[@ThunderHead289]

+1broncos7 on my stuff where i am running an electric fuel pump without a return line, that is what i do. else fuel gets hotter and hotter in the lines which makes it expand and ultimately gains enough pressure to blow ope the needle and seat. i think you are good with what you plan to do if it truly did shut down from an overly rich condition.

[@1broncos7]

+ThunderHead289 she shut down on here own and wouldn't run start. I checked everything, spark, fuel and air, then checked my oil and that's were I smelled the gas. So I sat and waited for the flat bed to pick us up. Is there anything that I have to do to my carb, after I change the jets ?

[@ThunderHead289]

you shouldnt have to. were your plugs wet at all? i hate that i have never made a video on it, but i run an 02 gauge in my galaxie, that thats how i found the vapor lock and what not. i always thought it was too rich, but actually it was lean. something to look into. they are 150 from aem on ebay and they work really well and eliminates carb tuning guess work.

[@1broncos7]

+ThunderHead289 haven't dug into her yet but, I will tonight. I'm going to start her up until I put the smaller jets in.

[@ThunderHead289]

just be careful, dont chase your butt here. if it died while idling that has nothing to do with jets, if it died while you were driving around, your choke may not be opening correctly (needs to open sooner/ doesnt open fully) next time your car floods, crank it over and just hold the peddle to the floor, she will light off. light contaminants in the oil (gas/water - not enough to change your oil level) will quickly vaporize and exit your oil as soon as the car is up to temp.

[@oscaralmanza4912]

my needle is leaking gas, i tried to adjust it and it still leaking, so you think my floaters have gone bad?

[@ThunderHead289]

Oscar almanza it is hard to say, pull the needle and seat assemblies first. they uncrew all the way from the top, and blow them off really well with carb cleaner. micro pieces of crap can get in between the sealing surfaces.

[@johnathonrambo]

New orings!

[@geraldparker9305]

I just put a eng. In my truck and it seem to run pretty good you turn the key and it would fire right up .the carb.is a 600 but it took. forever too get the eng. in. I took the truck to a trans. shop to get the trans. ajusted it been a couple of weeks now it won't start just turns over and I think the plugs are gas falded.should I just get it rebuilt I'm also using a Carter electric fuel pump? .

[@spdlsz]

no filter and it does move up and down. I have a glass fuel filter on before the metal fuel line that goes to each bowl I can see gas going through it

[@ThunderHead289]

How do you no there is no fuel? When you drop the bowl it's dry? Or no fuel comes out the sight plug. I mean, if you have fuel getting to the secondaries, and have fuel through the line and the needle and seat are working, you must have a blockage.

[@frankiehavocbroadnaxfranki8460]

6spdls1z28 98

[@davidasherii5696]

hello sir Im still having problem with flooding I've replaced fuel regulator 2 times and the seat and needle in the carburetor and the car will idle all day without flooding but once u go to drive it it starts to flood and shut down the motor

[@ThunderHead289]

+David Asher II how do you know it is flooding the engine exactly? Just out of curiosity.

[@davidasherii5696]

ThunderHead289

[@davidasherii5696]

once the engine stalls out I open the hood and take the air cleaner off the carb and there is gas in all 4 barrels of the carb

[@ThunderHead289]

David Asher II what type of fuel pump do you have on the car, do you run any spacers?

[@davidasherii5696]

ThunderHead289 on the fuel pump I'm not sure the previous owner had it done and by spacers are you meaning between the carb and intake manifold

[@heffdog007]

ThunderHead289, The holly I have looks exactly like the one you show on the video. I have that on a 350 ci classic truck engine and its been doing fine for a year or two since it was installed new. This is a weekend driver, kept garaged and protected. Lately the carb floods from the secondary upon startup now, a really rough idle. The idle won't hold unless I hold gas pedal at high idle and it stalls if I let it idle on its own. It leaks gas very slightly from that area while Its running, and slight white exhaust is out the back. This problem happens when the truck sits for 2-3 weeks and I go to start it. When this happens I let it sit for 3-4 hours and it miraculously starts and is fine. Maybe the float sets itself on its own......If I drive car more often without letting it sit the problem doesn't surface, only if it sits idle for 2-3 weeks. Any suggestions? Removing the sight port while its idling isn't possible as it won't stay running and I believe if I removed it I'd have gas pouring out of it anyway. Should I remove the float needle (top nut on the bowl) and clean it with carb cleaner and reinstall? What is the long term fix for this?

[@ThunderHead289]

Ah gotcha, thanks for the in depth explanation. Sounds like the float is sticking, I'm assuming you have to run ethanol blend gas? Probably just needs a good cleaning. You may have to pull the rear bowl and inspect. The float cannot self adjust.

[@heffdog007]

ThunderHead289 Yes this is California gasoline here and it is no friend of the classic car crowd here. I hear the gasoline in this state is rough on carburetor parts. Maybe its this crappy gasoline and its destroying the parts in this carb. You say pull the rear bowl and inspect....my auto mechanic skills are limited to basic maintenance stuff and pulling the bowl and inspecting as you suggest doesn't help me as I don't know what's involved in pulling the bowl or what to look for if I do. I learned from your video that the float can be adjusted somehow and that may very well be the problem. Either that needs adjustment (up or down) or something needs to be removed and cleaned (i.e. float needle). I have a mechanic who likes to spend my money and rather than troubleshoot this with an adjustment he wants to remove the carb and send it out to be rebuilt....I'm looking at a minimum $600 exercise for something that may just need a spot cleaning or adjustment.

[@ThunderHead289]

+Jeff Ferrier wow, I'd do it for 50 bucks if it was sent to me for god sakes. Test it on one of my cars before I sent it back to you also ha!

[@ThunderHead289]

i also made this video eons ago. pretty awful speaking it looks like i recorded it with a pineapple but it should give you a bit of guidance. as always, i will do the work for people and send them their unit back very cheap as long as they pay for parts and shipping.

[@ThunderHead289]

forgot to tag the video of course - kzbin.info/www/bejne/iIexeJeuebZlfpI

[@302highperformance]

cool you wouldn't know what size cam I could use on it

[@bigbooyig]

Great video run through. Thanks

[@deepbludude4697]

I'm looking for a 1" phenolic spacer for a Holley 500 2BBL. Anyone have any sources?

[@alandawson8665]

Deepblu dude make one

[@megasharkz1r]

didn't talk about power valve

[@ThunderHead289]

good point, most modern carbs have check balls in them to prevent power valve blow from flashback. still a good point. if all else fails and the car just wont idle at all, it might be what to look at. I actually just had a pvalve go bad on a 650.

[@DANTHETUBEMAN]

gud vid on the common things happening on a Holley street engine car

[@ThunderHead289]

DANTHETUBEMAN if i could go back, id mention something about running a return line. i run an o2 gauge in the car now and it makes a huge difference to have one. anything vapor lock related is gone. i had to rig one up since i drove my galaxie to virginia 1400 miles from iowa. and it is hottt down here.

[@DANTHETUBEMAN]

ThunderHead289 im trying to get away from a return line and do it all in one 3/8 hose elect pulp regulator set up with a regulator that controls the out put of the pump.

[@ThunderHead289]

i run a regulator as well with my return line. the electric pump burns up without it. i didnt have a return on my way to virginia and it burned the pump up. i now run a summit 140 gph pump with 14 psi regulated to the carb at 7.5 psi and a .060 thou restriction orfice on my 3/8 return line. my sending line is 7/16 and is plenty for my small block across the rpm board. (i run an o2 gauge so i know its not leaning out). you always want a bigger return line because you do not want to build pressure on that line. my .02