Fuel Mileage Tips and tricks

CashApp - $AirandFuelGuru

[@scottquasebarth677]

The information that you provide to us from your vast knowledge of carburetors is so important thank you my friend for all the time that you do to help us with our vehicles, God bless

[@holleycarbshowtosadvice40y90]

Thank you Scott.

[@richarddein6418]

I love the series. Keep it coming please. Your videos are tuning my car and have acquired all tools as mentioned. The results so far are astounding. 308ci with 4165 and tune becoming awesome.

[@holleycarbshowtosadvice40y90]

Thanks Richard.

[@L.A.Concrete]

Keep it coming! I have a 4190eg off a 79 Ford F-600 with a 460. The carb was originally on a 370 I built it about 10 years ago but knew nothing about tuning so I’m building it again and am going to install a wide band air fuel ratio gauge. So all the tuning you can show me the better

[@holleycarbshowtosadvice40y90]

I will do my best , thanks for watching.

[@timrayburn2461]

Glad to see you back.Keep 'em coming

[@holleycarbshowtosadvice40y90]

Thanks alot.

[@robertjohnson3550]

Great videos

[@ford351cleveland]

Hey man thankyou verymuch for this video and thankyou for listening to us its really appreciated great video

[@holleycarbshowtosadvice40y90]

You are very welcome. Please leave me some more information on your car.

[@b-17wingman37]

I have a 4180 that developed a rough idle after approx. 1 year so tore into it and found that the area where the primary meter block mates to had a lot of low spots or casting irregularities. I took a wet stone to it and it became more apparent where the low spots were. Put a kit in it and it is about 75 % better . I still have a low spot on the left idle transfer holes that is causing the rest of the rough idle.

[@holleycarbshowtosadvice40y90]

Are you working on the main body or the metering block?

[@keithiverson6687]

This is an interesting subject. I have a 6213 Holley 800 spreadbore on my mildly cammed Buick 455 and with the gas prices going up it would be good to get a bit more mileage out of it. The best so far is about 13mpg shortly after bolting it on, I should be able to get it higher.

[@holleycarbshowtosadvice40y90]

I think so , I believe a spread bore and the 4180 series holleys are both great , with the spread bore giving you both fuel economy and performance. Hope this information helps also follow along if your interested. I hope you will like and subscribe thanks.

[@keithhebert9334]

I really appreciate this video and the others that you make because I have put them together and got them running made them work and for the most part I know how to make them work right but there is little things like this that I overlooked that would help me out see I have acquired a whole bench full of Holley carburetors and Autolite 4100 carburetor and I want to fix them so I can eventually have them for use on my future projects one thing I would like to know is that how to identify as most of them that I got are like from the 70s is there a website or a chart that will tell me exactly what these list numbers are from

[@holleycarbshowtosadvice40y90]

Keith the only information I found is hemmings they cover some information on the old autolites. Hope this helps.

[@Scarlet_1971_cuda]

This is great. Keep it coming.

[@randallcribb668]

Thanks.

[@savoyblue777]

Very good Info keep this series going Thank you

[@holleycarbshowtosadvice40y90]

Thanks JD.

[@claythomas9509]

Good to see you back Randy! I didn't know if you were still with us.

[@holleycarbshowtosadvice40y90]

I'm still on the right side of the grass lol . Good to here from you.

[@claythomas9509]

@@holleycarbshowtosadvice40y90 I'm still trying to get that 460 running. I've gone through everything on the carb I can think of. Starting to think of other things it might be. Maybe I should send this carb out and eliminate it as a cause. Do you still work on them? Could I send it to you?

[@donnatalielucasheimbigner7598]

I have a tricked out Ford 400 engine that worked best with a 650 double pumper even though it is in a F-350 4X4 weighing over 6000 lbs. To get a bit better mileage I used most of the tricks here as well as a primary metering block from a 700 carb on the secondary side, drilled out the idle holes for a 4 corner idle, & installed a power valve 3.5" power valve. That allowed the use of jet sizes 3 smaller while keeping the AFR about 13 when the secondaries opened under heavy load (hauling/towing) with a low of 12.5 at full open full power with nearly 2 ton of feed loaded. The installation of a good AFR gauge is key no matter what you do because without it, yo really do't know how much fuel you can safely remove without burning a piston under load.

[@holleycarbshowtosadvice40y90]

I agree an afr gauge is a valuable tool , when trying to get best performance and fuel mileage.

[@michaelgiglio1571]

Tnx randy your best carby man i know. Also, milege is important now.

[@holleycarbshowtosadvice40y90]

Thank you, let me know if I can help .

[@MEC1955]

Do you have a 4224 .that you could explain how to make it street friendly in a 2 x4 tunnel ram application? Thank you and GREAT to see you back!

[@holleycarbshowtosadvice40y90]

That's a great old carb , but it's hard to calm down 1 to 1 mechanical carb , it's been a long time since I've even seen a 660 center squirter , I believe I would go a different direction. Good luck.

[@michaelgarrow3239]

Love your meter!

[@holleycarbshowtosadvice40y90]

Thanks .

[@wannwarriors]

Really enjoy your videos, I personally would like you to do a video on converting a holley from fuel to Methanol

[@holleycarbshowtosadvice40y90]

Will get to it as soon as I finish our current videos thanks.

[@wannwarriors]

@@holleycarbshowtosadvice40y90 THANK YOU

[@b-17wingman37]

I have been kitting carbs for many years, wrenched pro for 24 years but never came across an idle issue like the one on the 4180. I never really took time to chase down and fully understand a few things on the Holley. Thank`s for sharing your knowledge, really appreciate it .

[@holleycarbshowtosadvice40y90]

I worked for Ford for 27 years and I started with points an condenser and ended with EEC-5 OBD2, I saw alot of changes through those years and worked building engines an the old trans and ol 9 inche rear ends, but always loved building my carbs, built a lot of 4180s holleys, It never got old, well except me lol. Enough said. Take care.

[@holleycarbshowtosadvice40y90]

Let me know if I can help you with your 4180 holley, there a little different than a regular holley but a very good carburetor.

[@b-17wingman37]

Ok thank`s .

[@DadsToyBox]

Hi Randy. Thanks for the videos. I have a question about my Holley 4150 850cfm. The front 50cc squirter works great and shoots a ton of fuel when the car isn’t running. However, when it is running it struggles to squirt a decent amount. Sometimes only a small mist while it’s running. The result is a stumble and the afr goes lean. I’ve rebuilt the entire carburetor already. Any idea what it could be causing the problem?

[@holleycarbshowtosadvice40y90]

All right this might be a crazy one with that being said, if we have a full fuel bowl of gas that's not full of air and no crazy vibration in the engine , look at both check valves, the check valve slash counterweight under the discharge nozzle with the pointed end of the check facing down if that's good, take a small flat punch and lightly tap down on the counterweight to reseat it, be careful and lightly tap the counterweight not to damage it . The bowl has either a umbrella rubber check valve or a steel ball check , if you are using a 50cc pump you need to use the rubber check valve fuel bowl it has two return holes to fill the accelerator pump cavity up,don't know if this is the fix ,but the engine running seems to cause the problem maybe vibration affecting the check valves or not enough fuel volume or aerated fuel, just taking a stab in the dark ,but if you have the bowl with the steel check valve you need the umbrella style bowl to go with the 50cc pump and if you converted the carb from the 30cc to the 50cc pump make sure you use all the 50cc parts including the 50cc spring, diaphram, housing, arm ,cam everything.This is an unusual problem don't know which could be the fix at this point you have to start some where. Good luck.

[@DadsToyBox]

@@holleycarbshowtosadvice40y90 I’ve seen your video where you reseat the check valve. I will try that again but if I remember correctly I did that when I rebuilt the carb. It does have all 50cc parts and the rubber umbrella valve in the accelerator pump. I did not replace the rubber valve when I rebuilt the carb bc it worked before I rebuilt it and it looked ok. I may try to replace it with a new one.

[@StephenGiovi]

HI: I'm working on a 650 manual secondary that is showing on the No. 1 plug to be too lean, but the AFR is showing too rich. Do you recommend a bigger carburetor? Can I just jet it so that all the spark plugs color correctly? I have a under .5 lift Crower cam and a Weiand Speed Warrior intake.

[@holleycarbshowtosadvice40y90]

I need to know how your reading your spark plugs and more information like cam duration @.050, cubic inches, list number from your carb. we'll try to figure it out.

[@shawnbins203]

I have 2 Holley 80457-2 carbs. My understanding is they are calibrated leaner than the 1850’s. Would they be a better starting point for a tunnel ram set up? (Small block Chevy)

[@holleycarbshowtosadvice40y90]

I think your are right Shawn, what would be great if you had a couple 4180's they are so well calibrated. Don't know if your familiar with the 4180 , I showed part of one in the video, but most has annular boosters in the primaries and a two stage power valve and a four corner idle circuit, the two stage power valve helps with mileage and also the annular boosters and makes great performance , just a thought. Hope this helps.

[@MattsRageFitGarage]

I have an 1850-5 and a 80457, ran both on two different vehicles at the same time. I always have been happier with the way the 1850 with an electric choke conversion ran. Both were lightly used carbs that I completely rebuilt in exactly the same manner. The calibrations appear to be the same jetting wise, but I think there is something different in the metering blocks because the 1850 has way better overall performance for the MPG I got out of the two vehicles. I also ran the same Summit 600 carb on both vehicles so I know how they can both behave with the same carburetor as well, which is pretty much identical behavior.

[@bigboy3940]

I need help I'm having a problem with tip in .I get my idle set at 14 13.9 with afr Gage rpm at 900 idle .but when I push the gas it goes Lean to about 16.how do I get the afr to get richer please help.been trying to figure it out.truck runs great if I put afr at 11.5 idle then the leaning out goes a way .but it burns your eyes.

[@holleycarbshowtosadvice40y90]

Check accelerator pump arm for any play and adjust as necessary, check to see if the pump is squirting fuel the second you open the throttle if that's good then step up the size of your discharge nozzles, now if that don't take care of stumble let me know everything you have done to your carb, also make sure your timing is set right and advancing properly. Hope this helps.

[@plumbs7199]

I’m having trouble getting 14:1 cruise at 2500 rpm . 850 st Holley latest model . 408 Cleveland stroker , ported 3 v heads comp 294 b cam dur 250’s intake , 260’s exh. 106 lob centre , 105 int cent. 86 sec , 77 prim , 78 thou pvrc . Ib 76 hsb 35’s . Idle circuit.31 thou . Best I can get is 12.2:1 at cruise 2500 15” vacum . Could lean out the whole curve if I opened up the secondary blade stop ? Or should I lean out the idle circuit to .28 thou and the top ( billet metering block 3 hole) emulsion hole to .31 thou ? Has 6” vacum at idle . So just thinking that more air from the secondaries would lessen the transfer slot and lean out every thing . Looking at the T slot it’s more rectangle than square? Regards from Australia.

[@holleycarbshowtosadvice40y90]

Send me your carb list number also 14:1 fuel ratio is way to lean for that engine.

[@paulhershberger8774]

I have a Holley 670 on my 390 FE. It’s dialed in pretty close. On transfer slot steady driving my afr is about 12.8 to 13.8. When I nail it,it goes lean briefly. All the way to 20 on the afr. My idle restrictor is a .035 and my air bleed is a .075. If it’s rich before I wack it why is it going very very lean until the power valve and secondaries catch up? 670 truck avenger. NOS. Brown spring on vacuum secondary.

[@holleycarbshowtosadvice40y90]

Sounds like either your accelerator pump discharge nozzles are to small or your pump is not working correctly or both. Hope this helps.

[@TheBigstrat]

Hi Randy I have a Stroked 393 Cleveland using a 750 HP street The Carby developed an idling problem I have watched most of your videos which have been very helpful I have to have it idling at 1500 rpm when I select drive it still almost stalls I pulled it apart and sanded everything flat Jets are correct Float level correct I drilled the butterflies Transfer slot correct Timing correct Camshaft 106 lobe separation Vacuum is low so I put a 2.5 power valve Any idea what might be wrong It’s driving me nuts Thanks Stratos

[@holleycarbshowtosadvice40y90]

If it's in the idle circuit , first check to see if the right throttle plate gasket is used this is a common mistake, set the gasket on the carb and see if the gasket matches the idle hole and transfer slot hole line it up if you have the wrong gasket it will block the outer idle hole, both have to be open. Hope this helps.

[@TheBigstrat]

Also I have no problems adjusting the mixture screws Thanks Randy

[@robertomontenegro1153]

I live at 9300 feet altitude, I have an 1850 carburetor, the stock idle air bleeds are 0.0785” and the idle fuel restrictor stock 0.029”, camshat @ 0.050 212/212 single pattern LSA 110°, I must reduce the idle air bleed to 0.067” or 0.070” and increase the idle fuel restrictor to 0.035” and place them at the top of the metering block, for better gas mileage?

[@holleycarbshowtosadvice40y90]

Holley carbs are set up for sea level not 9300 feet elevation, a stock holley is way to rich at 9300 feet. Hope this helps.

[@b-17wingman37]

In your many years of experience have you ever seen one idle mixture screw protrude further into throat than the other ? I am always sure when turning in to seat them , not to apply any pressure. Bought carb new 30 years ago. When I rebuilt it i turned each screw out 1 1/2 turns like i always do and noticed one mixture screw protrudes into throat more than other , approx. .020 more . Have 20 inches of vacume at idle .

[@holleycarbshowtosadvice40y90]

I know I've had carb kits with different length mixture screws and I seen machining errors,the closer you look the more you find.

[@b-17wingman37]

ok ,thanks . The needle ends of screws were fine and it runs good . I will for sure be more careful to look over a new carb. the next time I buy one .@@holleycarbshowtosadvice40y90

[@ford351cleveland]

HELLO sir thankyou again for the video i would like to know what is a good Carb to buy then since i have a 1850-4 on a 351c 2v and i have a 760 street avnger on a 454 c10 which is new but have not driven the c 10 so i can you that carb but, i think its too big. So is it best to buy a modular carb or modify the 1850-4 or use the street anveger?? The 351c idles at 650 rpm with 16 degrees of timing and about 9 inches of vacuum at idle in drive with the secondarys cracked open for beter idle quality hope to hear from you

[@holleycarbshowtosadvice40y90]

I really need more information on your 351 cleveland engine and are you street driving or strictly drag racing, automatic or manual , gear ratio .ect ,

[@ford351cleveland]

@@holleycarbshowtosadvice40y90 thankyou for the reply its much appreciated. I only drive it on the street, its got a 351c with and stock shift kit C4 automatic trans a 3.32 gear ration with 29 inch tall tires with the Holley 1850-4 vacuum secondary manual choke siting on top of a dual plane Eldebrock performer intake with a 1 inch 4 hole spacer and a AEM wide band o2. its got 16 degrees timing at idle at around 650 Rpm my goal is to just cruise around with the best fuel mileage possible I also know that i have a 6.5 power valve in the carb which I think is too big since I only have 9 inch vacuum at idle. Any advice is welcome thankyou again

[@ford351cleveland]

@@holleycarbshowtosadvice40y90 HELLO sir thankyou again for the video i would like to know what is a good Carb to buy then since i have a 1850-4 on a 351c 2v and i have a 760 street avnger on a 454 c10 which is new but have not driven the c 10 so i can you that carb but, i think its too big. So is it best to buy a modular carb or modify the 1850-4 or use the street anveger?? The 351c idles at 650 rpm with 16 degrees of timing and about 9 inches of vacuum at idle in drive with the secondarys cracked open for beter idle quality hope to hear from you

[@SirCoolJerk1030]

@@ford351cleveland it's hard to beat an old reliable 1850 , you could try a 650 spread bore may improve mileage , but it's still hard to beat the 1850 , I would try a 4.5 or 5.5 power valve. The bigger carb may pickup some hp but at the cost of mileage , I believe I would stay with the 600 or try the spread bore ( hard choice).

[@steveproctor1748]

Tell us how to remove those glued on metering block gaskets without damaging the metering block. 😊

[@holleycarbshowtosadvice40y90]

If your talking about separating the metering block i don't know any easy way, if your talking about cleaning the gasket off the block they make a good spray gasket remover ill try an get you the name.

[@ralphparker9263]

Does Holley have kits for the 4180s or do get them from Ford?

[@holleycarbshowtosadvice40y90]

I know they are available through aftermarket, I don't know about Ford parts , I do know all the good kits I used had a base gasket that had 4 plastic spacers one at each stud and the base gasket was about 1/4' thick. Hope this helps

[@ralphparker9263]

@@holleycarbshowtosadvice40y90 Thanks I will check it out!

[@flinch622]

My understanding has been the sooner you can get on mains, the better. To that end, being overcarburated is a mistake - at least on a street motor. Transfer slot/power valve/acc pump don't do that great a job getting fuel atomized - boosters are far superior. To get there, optimizing the idle air bleed & idle feed restrictor is a must: there is no other means to tune fuel delivery through the transfer slot for a given bowl level. A street motor spends alot of time there.. Invest in a set of pin gauges to blueprint your starting point for bleeds/restrictors/emulsions before replacing anything if an AFR meter shows your ratio gets too fat at certain rpms. Sneak up on the rpms to avoid power valve opening causing confusion on the tune, then go after sudden acceleration in figuring out if pvcr restrictors need attention too.

[@holleycarbshowtosadvice40y90]

I understand where your coming from but you still have to remember the lower the rpm the less fuel you burn , what I'm thinking about is a good gas mileage car more so than performance a engine producing high torque at low rpm and modifying gear ratio and torque converter lock up and limiting rpm, but if your running at or above 2000 rpms then you have to use different boosters and work with 2 stage power valves and air bleeds and jets , always different ways to look at it . Let me know what you come up with, I'm releasing a video tomorrow on 2 stage power valves , hope you enjoy it .

[@jakefriesenjake]

I'm cruising at 3000 rpms with 4.11 gears and no OD. I just jeted down the primaries, (secondaries are wire tied) to get a better leaner cruise afr. Jetting down didn't really affect it. Going 62 mph at 3000, my gas pedal is barely being pushed at all. 383 stroker, 500 hp/tq, with a 650 speed demon. I must be on my transfer slots, still at 3000 rpms?

[@flinch622]

@@jakefriesenjake Not really - mains are seeing good signal between 2500 and 2800 most carbs. At 3k, I'm estimating you are using near 295cfm on that motor.

[@jakefriesenjake]

@@flinch622 I'll bet I'm still using some transfer slot still tho at that rpm. Need some more testing

[@69tinatforme]

thanks

[@holleycarbshowtosadvice40y90]

Thank you for watching.

[@trintwood8300]

Hey Randy do you have a parts vendor that you work with? Like if I tell em you sent me do you get something out of the deal if so I would really like to support y'all like that

[@holleycarbshowtosadvice40y90]

Trent I used to, but the company was bought out and they stopped selling in bulk now I buy most of my kits through summit.

[@TheSaxon25]

Gas prices are killing me Randy! Haha

[@holleycarbshowtosadvice40y90]

Saxon where have you been, good to here from you, those gas prices are killing all of us. Maybe we can figure out some way of saving gas.Have another video I'm releasing tomorrow on two stage power valves, hope you like it. Later man.

[@b-17wingman37]

Main body .Has low spots. Meter block is ok.

[@holleycarbshowtosadvice40y90]

Good job . I forgot to mention you can change either idle fuel restrictor just make sure the one your not tuning with is larger, why I told you to tune starting with the setting of the transfer slots first and then the idle air bleed next and the idle fuel restrictor last if need be, is when you restrict the idle fuel circuit your also restricting or leaning the transfer slot and that usually will cause a lean condition between idle and booster activation so its best to work with the transfer slots and next idle air bleeds that will usually cure the problem. Bigger idle air bleeds will lean the idle circuit . Hope this helps, if you have any questions just write me. Have a good one.