i just learned more about Holley carbs in this video than I have tinkering with them for the last 30 yrs. Thank you for sharing your knowledge!!!! You just got another sub!
Appreciate you getting back to me so quick. I’m going to put the fuel pressure gauge on with regulator & go back through what tech from Holley wants me to check. If no better probably going to send back. I’ll let you know what I came up with. Watched several of your videos that has helped me a lot. Been jacking with engines & toys for 40 years. Thanks
I've been following your tip and tricks, and you Randy are so right fixed two problems right from the start, I'm on a budget and the Holley I bought for $60.00, 600DP is working perfectly now. The man I bought it from said, he could never fix the problems I'm sure he hadn't seen your videos. Once again, thank you. Yea 850 baseplate on 750 nice. I'll be looking for a budget on a 750 soon.
I know this is an old video, but I just wanted to say thanks for the tips! I'm fairly good with Holley's and this just reinforced what I figured I needed to do.
You are the man! I am having this exact hesitation problem on a old Holley 2300 on a Chevy Nova. You helped me a lot. Greetings from Buenos Aires, Argentina.
I watched this video and came to realize i thought i knew alot about holleys since i have ben using them fixing them and rebuilding them for 30 years but i never knew the exact science behind modifying them .. since your kind enough to try n educate me ill hang around n listen ..lol ..thanks for the free education .. Glenn from east Tn !!!!
You know I rebuilt thousands of carburetors , before ever making improvements and modifications to the fuel curve , I guess a lot of it comes from my love of racing. Thanks and good luck.
Seating the check valve in the pumper well with a punch is a good tip. The valves will stick sometimes if the car isn't driven often. Like race cars or classic weekend drivers. Good stuff 👍
It is important to know the check valve and counter weight is working properly. Make sure its a very light tap with a small hammer. Thanks for watching.
@@MHM4V3R1CK it went perfectly, all the settings were out so I just followed the videos and it ran the best it had in my 4 years of ownership , just in time to sell it !!!!! Wish I'd found d this channel along time ago. Cheers.
Great info , you never touched on pump cams , I’m having a stumble on my CSU Holley that appeared after being parked for winter and you gave me a new idea to check into so thanks .
We will be making a pump cam video soon on the Holley carburetor . check your accelerator pump check valve its underneath your discharge nozzles and lot of times that little check valve sticks, remove the Phillips head screw that holds the discharge nozzles ,and then take a fine pick and just move the little check valve around just a little and don't move your throttle when you're doing this , because the check valve will come right out and down into your motor and just wiggle it around a little with that pic and then put it all back together , if this is the problem it usually takes care of it. If it's always had a stumble refer back to my last video, hope this helps if not let me know.
You may have to go to a 50cc pump , and 50cc pump cover and arm and use the brown pump cam , then keep increasing your pump nozzles until the hesitation goes away .hope this helps.
I have a Holley 750 DP and working to figure out why only under power, the motor stumbles about 3 times back to back every now and then. Just cruising around, everything is right with the world if i have air flow but after sitting at traffic lights and the temp creeps up, i have this issue. I have a 6.5 power valve due to 12 inches of vacuum and float levels are good. Also have adjusted the pump arm to .015 of clearance with wide open throttle and response seems perfect.
How high does the engine temp get and this only happens when your idling with temp rising, I don't think this is going to be an accel pump issue , let me know when it stumbles does it cut off or does it back fire through the carb or exhaust , what helps to get through the stumble , need all the information you can give me.
@@holleycarbshowtosadvice40y90 Thanks for replying!! The temp if i get caught at a full rotation at a traffic light, gets up to around 200 ish and if i take off at a normal speed, it stumbles about 3 times and acts as if the motor shut off but i just let off the gas and it never quite kills the motor.A few years ago, it killed the motor but it re-fired. No backfires of any kind. I have the accelorator pump set just as the throttle is being applied and have a discharge at the exact time I also have .015 left over for the pump arm during wide open throttle. I'm running dual electric fans that come on around 130 degrees.
Chad shoot me some pics of the fuel system, carb , spacer and the fuel pump and fuel lines under the hood or electric pump and where the fuel pump is mounted verses the fuel tank also pics of distributor and if your running a ballist resistor and are you using original ignition wire feeding distributor and what kind of distributor and I will give you a list of things to check. My Email is Racingbigblockchevyman1121@gmail.com. I'll try my best to help you.
I have been watching your vidioes for a while and they are very informative I have learned a lot about carburetors especially on modifying the idle circuit to regain the idle adjustment at the needle that vidio was great! keep up the great vidioes.
I have a quick fuel 750 street/strip manual secondary. Mine stumbles right after you hit the gas, then going down the road at roughly 3000 rpm. 30 cc pump, 33 squirters in front, 74 jets in front 84 in rear on a 383 sbc 9.5 to 1 aluminum heads, small comp cam Havent checked timing but i went up from 28 to 31 squirter, then a 33 with no luck. Fuel level is half way up the sight glass. It always has a stumble though regardless of the carb so timing could be off. Very frustrating, makes me want to go efi.....
With the engine off, look down the carburetor throat and as you move the throttle make sure the pump is squirting the moment you open the throttle. If it has any delay at all check accelerator pump arm for any clearance between the arm and pump if so adjust the pump arm so it has no clearance at closed throttle, the only other thing that can cause a delay in the pump squirting are the two check valves in the pump circuit. Always check your timing first before you tune the carb. Hope this helps.
@@holleycarbshowtosadvice40y90 Hey man, I'm trying to adjust my timing, pretty sure I need to advance it a couple degrees, but the distributor feels like it's dang near welded to the intake. I took the hold down bracket completely off, soaked the base with Kroil every day for a week straight, still no dice. Should I try heat?
Turns out, i had to up the jets by 2 from 71's to 73's and. I'm learning that for every 30 or 40 degree drop in temp outside i need to drop the jet #'s by a couple or a few. So when the temp starts to drop in the fall, i need to raise the jet by 1 or 2 from 73's to 74 or 75's and then when it begins to get hot outside, i need to drop it back down to 73's or just pay more attention to hesitation and how it's behaving. The carb was running lean with hesitation off idle and backfiring under a load. the plugs porcelain was solid white and chalky. the tips looked ashy which took me down the lean road.
It helps to control the idle with big cams with lots of duration, I believe it's easier to stage your car . Now because of extra air flow at idle, some times you can tune out a lean part throttle issue ,but when your at wot not much difference. There are more advantages.
So i run a trans brake in my car.. and we have been having a problem with the car wanting to die when i floor the gas while holding the trans brake. Do you think this could be a carb problem?
That could be many things could be fuel curve or fuel delivery problems or ignition, could be primary or secondary ignition, ignition box ect , so many components, I know this might not help , but usually fuel, ignition or timing or bad connections.
I have a Holley 750 dp that I acquired it's used seems to work fine but have noticed that the rear accelerator pump arm doesn't touch the pump cam until it's about 1/2 open could it have the wrong link rod on it to cause this what else should I be on the lookout for that could be the issue. Looks like it has been changed to the bigger 50 cc accelerator pump on the rear bowl. I don't know the history of this carb. But I'm thinking it's got the wrong linkage rod on it. What's your thought about this.
You need to check everything they did, 50cc conversion consist of 50cc pump housing, diaphragm , and a taller spring, also the accel pump arm is different and pump cam, most of the 50 cc pump cams are brown, probably has wrong pump arm , but check all of it to make sure they did the install correct. Hope this helps.
I have a stripped thread in the accelerator pump discharge nozzle. Is it possible to use a helicoil insert to reinstate the thread?. Will that have any negative outcome, using a helicoil? Thanks.
I see Jacksonville.. I have a 850 demon with 33 squirters .. it's fine unless I floor it then it studders has a little hickup then clears up. Should I go bigger squirter???
It's possible you could need more squirted, alot has to do with the cam and ignition timing ,the more cam , the more squirted, usually .033 is enough , look at your ignition timing too not enough timing or not coming in quick enough , so many things can cause this ,some times not enough converter , even a weak ignition coil can cause this ,if I new what you had in your engine , compression , cam specs , cu in timing , intake manifold that would help me , make sure zero clearance in acc pump arm , send me so more information and we will do our best .
Does this magic work on all car carbs? I have a Honda Civic EG3 from 1995 with a 1,3l carb engine. The engine runs like a swiss clock but the carb sometimes gets dirty and starts having it`s own mind. Can I do the same to my car?
Most carburetors just need a rebuild kit. They are calibrated for the specific car there made for. I'm not sure what you mean by starts having its own mind.. if you can explain more clearly mabe i can help.
I have a hesitation after shift (standard shift), just normal driving. It doesn’t backfire, honestly I think it’s rich. What can I do about richness. Brand new (refurbished) from Holley. It’s on .30 454, it’s got low end cam for towing. Idle to 4,000 rpm. Straight out of box 2 of the mixture screws all the way in. It’s rich at idle, doesn’t adjust out good. My old 4779 runs better but I wanted electric choke & vacuum secondaries. Float level is right, pump set right, transfer slots right. I’m running factory fuel pump, got a regulator & gauge coming before I send back to holley, but I’d rather fix it. All they going to do is flow it again & it was already supposed to have been LOL. Any suggestions I may try. Thanks
Woody I believe I would send it back to holley , when you see two mixture screws all the way turned in, that's a red flag. If you won't to fix it your self it needs adjustability, changeable air bleeds idle fuel restrictions pv restriction ect. Also need to know the color the plugs are burning, type of distributor mechanical or vacuum advance and mechanical. And if vacuum advance is used is it hooked to manifold vacuum or ported vacuum at carb , there is so much information needed, you decide and I'll help you any way I can , if it has know adjustability I would definitely seed it back to holley. Hope this helps.
I need help brother, I have a Holley 650 and no gas is squirting..happened out of nowhere! I changed the accelerator pump diaphragms, brand new fuel filter… pressure is at seven and still nothing no squirt in the chamber. What do you think it is? Thank you
Usually the check( slash counter weight) under the squirter screw gets stuck, be careful not to let it drop down the intake. If it keeps happening you may have to clean and gently reseat the check/ counter weight using a small punch and small hammer. lol
What about a lean stumble where the throttle is pushed so lightly, in second gear and at around 2000 rpm, that xLr8r pump isn't even being used? My original ifr in my 650 speed demon double pumper was at 0.033", then I put in a set screw drilled out to 0.026". Could that do it? It didn't do it before. Timing is 24 initial, 38 total. Thanks
The accelerator pump should always squirt unless the check counter weight is not seating , now .026 is not enough usually i run .035.. then make sure you have your transfer slots around .035 . That.should take care of your problem.
@@holleycarbshowtosadvice40y90 Ok thanks, but the ifr was 0.033", too rich at 3000 cruise. I got the cruise afr pretty good now with 28 ifr, and jetting down from 74 to 66. With doing that, Wot is a touch lean at 13.5 afr (primary only), so I will drill the pvcr from 059, to 064". The nozzle is 35, maybe try the 37, see what happens. The pump does squirt its all good, but the throttle is pushed so lightly, it might not be enough. If I stab it quicker, it's good..
Jake before you drill your pvcr start by changing your ifr circuit back to .033 to .035 then correct your 3000 cruise with a main jet change and your wot may be ok get your air fuel correct then check your 1300 to to 1800 cruise and check ifr fuel ratio.hope this helps.
I have a hesitation, but its not from the squirter. It's a lean spot because the secondaries are opening too soon. I tried the heaviest and the second to heaviest springs (ive actually trued all the springs) and I still get a slight hesitation before the secondaries open. What else would you try? I tried putting a small strand of wire in the high speed air bleeds, but it did not help. I've also tried power valves from 5.5 to 10.5. My idle vacuum is about 18 inches. it's a heavy truck, 6600 pounds, it has a manual transmission with a 4.56 rear end. The engine is a stock 454, they have a very small cam with 195° duration at .050, so it doesn't really turn a lot of rpm's, 4500 max. Ive tried a 600 and 800 edelbrock, a 600cfm 1850 holley and a 670 street avenger. My timing is at about 13 initial with about 38 total. Im not sure what to do next. Any help would be appreciated.
What kind of distributor are you using, is it all mechanical or have a vacuum advance , and if so where is your hose hooked to on the carb for the vacuum advance. Which carb are you using now, if it's a 1850 let me know does your secondary diaphram housing use a ball check or a small .045 hole for the vacuum to work the diaphram.
@@holleycarbshowtosadvice40y90 I am using the 670 street avenger right now, im not sure if it has a ball or the small hole. The distributor has vacuum advance also. I would like to go back to the 1850. It has the small hole, I do know that.
Ok make sure your distributor vacuum hose is hooked to the metering block which is ported vacuum on most carbs or could be in a different place its according to the carb, you don't won't manifold vacuum. Also if you won't to slow down the secondaries opening use the ball Check housing its ok to switch housing if you have to , alot of people leave the ball out and it will open secondaries early.hope this helps.
@@holleycarbshowtosadvice40y90 yeah, thanks that helps.its nice knowing which one was the best direction to go. We'll see if it fixes it. Do you have any guesses on if the 670 has the the small hole or not?
my 4160 Cab on my 390 engine, i had to spray gas into the Carb for the car to start it wasn't spraying when you press gas, , i rebuilded the carb now it's spraying but now i have to press the gas to start the car once i stop pressing gas car turns off, any suggestions please?
Check valve leaking back into the carb and a hesitation upon excelleration. I thought about the hammer tap but since it was a new Holley I didnt do it. 650 double pump etc. Now, I still have minor flooding after a warm engine shut down and a hesitation after trying everything else, so next I will try the hammer tap trick. Thankx for the video and advice.
My car has a 383 with a 6 barrel configuration. Do you have any videos showing vacuum hose connections to/from the carburetors to the engine? Also, the adjustment of the linkages and return spring placement?
What kind of tri power setup do you have, are the front and rear carburetor vacuum operated , they usually are , it runs primarily off the center carb and the front and rear carbs come in at higher speeds If you have a distributor with a vacuum advance ,you will wont to run your vacuum hose from the distributor to the center holley 2 barrel on the passenger side metering block.hope this helps , if you need more help let me know.
@@holleycarbshowtosadvice40y90 Thanks for the follow-up. I can't tell you much about the power setup, for I bought the car used (translate auction), but it is a '69 Plymouth Roadrunner with a 383 and a Pertronix coil/distributor, which has a vacuum advance. The vacuum connections that I am interested in are the ones from the larger ports on the passenger side of the center carb (one near the top and the one near the bottom). I'm thinking they are to attach to a breather valve (driver side) and/or a PCV valve (passenger side), but which goes to what? The current setup is that the breather valve connects to my air filter (driver side); the lower port from the center carb attaches to the PCV valve; and the shop bored a hole into bottom of the air filter (passenger side) and installed a port and connected a vacuum line from it to the upper port of the center carb (I don't think they should have done that). It's a bit wordy, but hopefully not confusing. 🤔
@@dogdoc1 I think the "mystery" hose connection that you mention near the end of your comment is probably a float bowl vent plumbed into the air cleaner which is perfectly fine and a good idea.
The vent probably went to a charcoal canister originally. It could have been left open to unfiltered atmosphere where dust and dirt can make it's way into the bowl but plumbing it to filtered air is a better idea.
Is it a two circuit or three circuit and what size cfm, might be best to call pro systems and talk to them, you can come up with a hundred different fuel curves.
I have a question well two actually. The first one is what does it mean if gas shoots out of the fuel bowl vents? And two in your opinion what may be the cause of my car sputtering out once it starts? The car will start but will die unless I keep my foot on the gas but once it heats up the engine is fine. Just can't seem to figure why it does both. Hopefully you can help me out. Thank you and I appreciate your video felt I learned something.
Gas coming out of your vent tubes could mean several things , fuel pressure is high, should be 6psi or less if its high correct that first , also bad or sticking needle and seat , bad float , or bad sealing surface around the needle and seat o ring or the o ring itself , anything restricting the vent can cause it, hope this helps . On your second question I need to know if your carburetor has a choke.
Maybe you can give me a suggestion on jetting for a 780 vacuum sec. It's on a 350 Chevy with.489/.504 Lunati, 185 cc runner ProMaxx heads, Air gap intake, 3000 stall, 3.73 gears. Car ran 13.07 in the quarter with a 600 Edelbrock. I have 70 in the front on the 780 with a 6.5 power valve, 76 in the rear with a power valve plug. Does this sound close?
If you have a air gap dual plane intake, try jetting up at least two sizes on primaries and secondaries see if that helps performance.also keep reading your spark plugs .I Make a 1/8 mile pass then I kill the engine , coast to my pit , pull the plugs and read how they are burning.
Hi of the topic how would you determine the correct power valve size for a ski boat ? I’ve been told boats have a different load so I can’t do the same procedure as a car
Usually its a lean accelerator pump, with engine off look down your front primaries and while opening the throttle watch your pump squirters they should squirt fuel from the time the throttle moves. If not adjust accelerator pump arm where there is no play.If they squirt fine then change your pump squirter to a larger size, by removing carburetor and look on the side of the squirter, the size is usually marked on the side of the squirter or discharge nizzle. Start off three numbers larger, make sure When you remove the nozzle you dont loose your check valve under your squirter. The reason i told you to remove the carb is if that check valve falls out or you move the throttle the check valve can fall down the intake and damage the engine. Hope this helps
There is alot to air bleeds and I will do a video later, but if you make your air bleed bigger it will lean the mixture, and a smaller air bleed will richen the mixture, there is so much more you need to know, will have to cover the rest in a video. Hope this helps.
The check ball slows down the opening of the diaphragm, some holleys use a fixed orifice instead of the check ball, then fine tune with your diaphragm springs.
@@holleycarbshowtosadvice40y90 Iv always taken the check ball out, thought they run ok. Is it still better to use them. Do you use them on your carbs Randy.
Sometimes I use the ball checks but mostly use the fixed orifice, and tune from there. Study the vacuum feed passages for the diaphragm. Hope this helps.
I have a question; i have a stock 360 in my d150 and have been driving it for a while, it has had slight dips while cruising but nothing major. I checked the plugs and they where really light so i jetted it up from 71 to 73. Now it bogs while i cruise. I can drive at 1/3 throttle and it bogs/hesitate for a second and gets back up. Also have alot of hesitation while rolling down hill with no throttle, but it has done this all the time. It is a 650 holley 4160 w/rear metering block.
I am having a hesitation off idle, below 2k rpm. It also does it at cruise when im barely on and off the throttle. Should i adjust transfer slot, ifr's or the low speed bleeds? Orange pump cam, although the hesitation is at very light throttle, it spikes lean and hesitates.
Is your accelerator pump discharge nozzles clean and working , next check and see what size the discharge nozzles are , usually an off idle stumble is due to not enough accelerator pump shot, may have to go at lest four sizes bigger. Hope this helps.
@@holleycarbshowtosadvice40y90 its a brand new Quick fuel 670 Brawler. The hesitation is with very light throttle, like driving through a parking lot slowly, just one little spot, it spikes lean and will stay there if i keep that same throttle position.. 31 squirters in it, orange cam.
Alright make sure there is no play in accel. Pump arm and try a .035 nozzle, if that don't work , try a bigger idle fuel restrictor and make sure your float level is adj. properly ,you can also try a smaller idle air bleed both will richen up low speed , as long as this problem is happening before the booster starts flowing. hope this helps. ps make sure your ignition timing is working properly and advancing off idle.
Where I usually get mine is off the snap on truck or matco tool truck , I'm sure any quality tool company would have them., I ask for carburetor drill bits and they usually will sell you the little hand held pin vise to go with the drill bits..
What if at 2000 rpm cruise and you step it quick and then it acts like it wants to die maybe it dies for a second until you lift your foot? Could that be the secondaries pump nozzle on a DP?
That's a good possibility , to much pump clearence or blockage at discharge nozzles primary's or secondaries, or needs bigger discharge nozzles, there is so many things to look at , process of elimination don't forget timing and advance, thanks for watching.
If everything checks out ok , either drill your accelerator pump nozzles about .005 larger or change pump nozzles to .005 bigger , this is where having a set of guage pin to size the hole is great to have, the number on the discharge nozzles #25 means its .025 thousandths , note if it's never been drilled before.
Your explanation of the function of the check weight could leave to confusion. What you said was that when the fuel comes up out of the pump that check weight has to stop it, and that's not true. It's when the fuel STOPS coming up out of the pump that the check weight has to close to stop the suction of the pump from pulling the little fuel, and subsequently air (because it's far easier to pull air than it is fuel), back into the pump. It should also be noted, that sometimes it's not a checkweight but a check ball and spring. Also, if someone is going to measure their squirters, they need to measure BOTH sides, not just one.
It think you should have covered the power valve ,be for going to the squiters ,that's just me and where I would have made sure I had the right power valve 1st ,great video well done
It's very unusual to have a power valve cause a stumble right off idle and it's a lot easier and cheaper to change accel. pump adjustment or discharge nozzle size than to open up the carburetor .
Sounds like a good combination , maybe a little tuning , I put a 2 barrel motorcraft carb on my son's 258cu.in. straight 6 in his Jeep , I think all I changed was to a leaner set of jets not sure on the cfm size , . You may not have to change anything, let me know if I can help. Thanks for watching.
Yes get the list# off the front of the choke housing , then cross list# number to get cfm size , for instance if list# is 3310-2 its a 750 vacuum secondaries the 2 means second generation.
Not usually , most of the time it will be in the accelerator pump , either pump not squirting or out of ajustment, or not enough pump shot. this is the most common problems.
You didn't mention the accelerator pump cams . Wrong cam ,worn cam will cause a off idle stumble. One screw change out the accelerator pump cam iv run across people install the wrong cam several times.
@@holleycarbshowtosadvice40y90 I could use some advice. I built a 468, 454 at .60 over. 10:1 compression with AFR heads. I think I under carbed it with a 750 vac But lol after breaking in the cam I'm 13 minutes I sucked down almost 5 gal gas. I think my power valve is off. I'm running the big mother thumper cam. Any suggestions.
@@holleycarbshowtosadvice40y90 also I rebuilt the carb. I blew out the air bleeds one was stuck. I like your advice on the 50 cc and mods for a squirter
Well I’m going to send it back for refund. I really like to find a 650 classic vacuum & electric choke. Can’t justify buying new for this truck. If you happen to run up on something I’d appreciate a hollar. Thanks Randy for your help🤙
I had a 600 holly.It had a stumble, plus bad acceleration on my 351w.I fixed it, with a 750 Quick fuel slayer.Drives like I have 50 more hp at least.I will never use holly again.
@@holleycarbshowtosadvice40y90 The design of the slayer is totally different than the holly 600 I had on the motor.Maybe holly bought them out because they knew it was better than there's.The slayer is easy to adjust with more fine tuning capabilities than the old holly 600.All I'm saying is my motor runs a whole bunch better than before.
i just learned more about Holley carbs in this video than I have tinkering with them for the last 30 yrs. Thank you for sharing your knowledge!!!! You just got another sub!
Thank you.
This is the video I’ve been looking for for 2 months!! Thank you sir!!
You are very welcome.
That information helped me out of my hesitation. Thank you!
Glad I could help.
Thank you for sharing your knowledge. I'm dealing with this problem right now so it's helping me a lot!
Thanks
This one video just solved all my issues that Ive had for months. excellent work by both yall. Thank you for the knowledge
Glad I can help.
Huge Thankyou!! I’ve been working on Holley carbs for many years, & I’ve just learned a lot from you!!
Thank you.
Appreciate you getting back to me so quick. I’m going to put the fuel pressure gauge on with regulator & go back through what tech from Holley wants me to check. If no better probably going to send back. I’ll let you know what I came up with. Watched several of your videos that has helped me a lot. Been jacking with engines & toys for 40 years. Thanks
Good luck.
I've been following your tip and tricks, and you Randy are so right fixed two problems right from the start, I'm on a budget and the Holley I bought for $60.00, 600DP is working perfectly now. The man I bought it from said, he could never fix the problems I'm sure he hadn't seen your videos. Once again, thank you. Yea 850 baseplate on 750 nice. I'll be looking for a budget on a 750 soon.
Thanks Senia. l'm glad the video helped , hope to do the 850 throttle plate to the 750 main body soon, thanks for watching.
I know this is an old video, but I just wanted to say thanks for the tips! I'm fairly good with Holley's and this just reinforced what I figured I needed to do.
Thanks Justin I appreciate it.
You are the man! I am having this exact hesitation problem on a old Holley 2300 on a Chevy Nova. You helped me a lot. Greetings from Buenos Aires, Argentina.
I'm glad I could help, have a great Christmas.
I watched this video and came to realize i thought i knew alot about holleys since i have ben using them fixing them and rebuilding them for 30 years but i never knew the exact science behind modifying them .. since your kind enough to try n educate me ill hang around n listen ..lol ..thanks for the free education ..
Glenn from east Tn !!!!
You know I rebuilt thousands of carburetors , before ever making improvements and modifications to the fuel curve , I guess a lot of it comes from my love of racing. Thanks and good luck.
Thanks Randy. I find your videos really easy to understand and informative. You have helped me out tremendously. Thank you so much.👍
You are very welcome
Little things that mean a lot. Thank you for sharing your valuable information, "Happy Motoring"
You are very welcome.
Great info! Thank you for putting this video on here!
Thank you for watching.
I really appreciate you sharing all your knowledge, was about to give up and go efi. THANK YOU!!!
Glad I could help
Seating the check valve in the pumper well with a punch is a good tip. The valves will stick sometimes if the car isn't driven often. Like race cars or classic weekend drivers. Good stuff 👍
It is important to know the check valve and counter weight is working properly. Make sure its a very light tap with a small hammer. Thanks for watching.
@@holleycarbshowtosadvice40y90 Yes, recently had problem with sticking check valve in 650 DP, delaying pump shot. Good tip. Thanks.
I would watch a 2 hour video on carburetors. great vidya. Thanks for helping us!
Thank you, and if I can help you please let me know.
Great video. Never thought about lean condition in a stumble, always went straight to the power valve thinking it was blowed
Thanks for watching
My 472 Cadillac with 4160 just keeps stalling on acceleration from idle. thank god I found these videos I'm on it tomorrow.
How did it go?
@@MHM4V3R1CK it went perfectly, all the settings were out so I just followed the videos and it ran the best it had in my 4 years of ownership , just in time to sell it !!!!! Wish I'd found d this channel along time ago. Cheers.
Good luck .
Thanks for taking the time to share, great info!
Thank you.
Great info , you never touched on pump cams , I’m having a stumble on my CSU Holley that appeared after being parked for winter and you gave me a new idea to check into so thanks .
We will be making a pump cam video soon on the Holley carburetor . check your accelerator pump check valve its underneath your discharge nozzles and lot of times that little check valve sticks, remove the Phillips head screw that holds the discharge nozzles ,and then take a fine pick and just move the little check valve around just a little and don't move your throttle when you're doing this , because the check valve will come right out and down into your motor and just wiggle it around a little with that pic and then put it all back together , if this is the problem it usually takes care of it. If it's always had a stumble refer back to my last video, hope this helps if not let me know.
Thanks will do , this is an extreme street strip turbo big block with huge power that typically has very good street manners .
Man I have a 71 nova big block my self, there's no substitute for cubic Inches.
Holley Carbs: How To's & Advice ,40 yrs of exp. you’re right there 555 cubes for me
You may have to go to a 50cc pump , and 50cc pump cover and arm and use the brown pump cam , then keep increasing your pump nozzles until the hesitation goes away .hope this helps.
I have a Holley 750 DP and working to figure out why only under power, the motor stumbles about 3 times back to back every now and then. Just cruising around, everything is right with the world if i have air flow but after sitting at traffic lights and the temp creeps up, i have this issue. I have a 6.5 power valve due to 12 inches of vacuum and float levels are good. Also have adjusted the pump arm to .015 of clearance with wide open throttle and response seems perfect.
How high does the engine temp get and this only happens when your idling with temp rising, I don't think this is going to be an accel pump issue , let me know when it stumbles does it cut off or does it back fire through the carb or exhaust , what helps to get through the stumble , need all the information you can give me.
@@holleycarbshowtosadvice40y90 Thanks for replying!! The temp if i get caught at a full rotation at a traffic light, gets up to around 200 ish and if i take off at a normal speed, it stumbles about 3 times and acts as if the motor shut off but i just let off the gas and it never quite kills the motor.A few years ago, it killed the motor but it re-fired. No backfires of any kind. I have the accelorator pump set just as the throttle is being applied and have a discharge at the exact time I also have .015 left over for the pump arm during wide open throttle. I'm running dual electric fans that come on around 130 degrees.
Chad shoot me some pics of the fuel system, carb , spacer and the fuel pump and fuel lines under the hood or electric pump and where the fuel pump is mounted verses the fuel tank also pics of distributor and if your running a ballist resistor and are you using original ignition wire feeding distributor and what kind of distributor and I will give you a list of things to check. My Email is Racingbigblockchevyman1121@gmail.com. I'll try my best to help you.
Thanks so much I was having that hesitation and I did what you said and it runs like a top now.again thanks.
Doug glad I could help, thanks for watching.
Great video and awesome info. Thanks for you help, solved my issue! Keep it up, man!
Glad to here that.
Thanks for the info and your time!
Thank you for watching.
Very informative - easy hear and follow, thank you!@
You are most welcome.
I have been watching your vidioes for a while and they are very informative I have learned a lot about carburetors especially on modifying the idle circuit to regain the idle adjustment at the needle that vidio was great! keep up the great vidioes.
Randy. Thanks for the kind words I should have some more Holley mods soon.
I have a quick fuel 750 street/strip manual secondary. Mine stumbles right after you hit the gas, then going down the road at roughly 3000 rpm. 30 cc pump, 33 squirters in front, 74 jets in front 84 in rear on a 383 sbc 9.5 to 1 aluminum heads, small comp cam
Havent checked timing but i went up from 28 to 31 squirter, then a 33 with no luck. Fuel level is half way up the sight glass.
It always has a stumble though regardless of the carb so timing could be off. Very frustrating, makes me want to go efi.....
With the engine off, look down the carburetor throat and as you move the throttle make sure the pump is squirting the moment you open the throttle. If it has any delay at all check accelerator pump arm for any clearance between the arm and pump if so adjust the pump arm so it has no clearance at closed throttle, the only other thing that can cause a delay in the pump squirting are the two check valves in the pump circuit. Always check your timing first before you tune the carb. Hope this helps.
@@holleycarbshowtosadvice40y90 Hey man, I'm trying to adjust my timing, pretty sure I need to advance it a couple degrees, but the distributor feels like it's dang near welded to the intake. I took the hold down bracket completely off, soaked the base with Kroil every day for a week straight, still no dice. Should I try heat?
Turns out, i had to up the jets by 2 from 71's to 73's and. I'm learning that for every 30 or 40 degree drop in temp outside i need to drop the jet #'s by a couple or a few. So when the temp starts to drop in the fall, i need to raise the jet by 1 or 2 from 73's to 74 or 75's and then when it begins to get hot outside, i need to drop it back down to 73's or just pay more attention to hesitation and how it's behaving. The carb was running lean with hesitation off idle and backfiring under a load. the plugs porcelain was solid white and chalky. the tips looked ashy which took me down the lean road.
Good job.
Thank you for sharing your wisdom .
Thank you.
Very good information. Keep the videoes coming!
Thanks , will have some new videos soon.
Thank you for all the info and Sharing brother need to do this today mine runs has no power falls in it's face
Thanks and if I can help let me know.. have a good one.
@@holleycarbshowtosadvice40y90 u also sir appreciate you
Informative tuning video. The link to the Pin set seems to be a dead link.
Charles just google pin gauges .011 to .060 thousandths. Hope this helps.
Perfect! Thanks for the good tips 👍✌
Your most welcome
Why do some 4 barrels have 4 corner idle screws if the secondres dont open till higher reves.
It helps to control the idle with big cams with lots of duration, I believe it's easier to stage your car . Now because of extra air flow at idle, some times you can tune out a lean part throttle issue ,but when your at wot not much difference. There are more advantages.
Thank you for all the information
You are very welcome.
Very informative. Thanks for the video!
Thanks for watching
I’m been going pretty awhile to tune my carburetor given it’s a blo thru it’s pretty challenging
Thats Great.
Excellent details. Thanks a ton.
Your welcome.
Always good info. Thanks
Thanks for watching Doug.
So i run a trans brake in my car.. and we have been having a problem with the car wanting to die when i floor the gas while holding the trans brake. Do you think this could be a carb problem?
That could be many things could be fuel curve or fuel delivery problems or ignition, could be primary or secondary ignition, ignition box ect , so many components, I know this might not help , but usually fuel, ignition or timing or bad connections.
I have a Holley 750 dp that I acquired it's used seems to work fine but have noticed that the rear accelerator pump arm doesn't touch the pump cam until it's about 1/2 open could it have the wrong link rod on it to cause this what else should I be on the lookout for that could be the issue. Looks like it has been changed to the bigger 50 cc accelerator pump on the rear bowl. I don't know the history of this carb. But I'm thinking it's got the wrong linkage rod on it. What's your thought about this.
You need to check everything they did, 50cc conversion consist of 50cc pump housing, diaphragm , and a taller spring, also the accel pump arm is different and pump cam, most of the 50 cc pump cams are brown, probably has wrong pump arm , but check all of it to make sure they did the install correct. Hope this helps.
@@holleycarbshowtosadvice40y90 pump cam looks to be more of a light tan color then brown. Could be faded though. Time to do a rebuild Thank you
I have a stripped thread in the accelerator pump discharge nozzle.
Is it possible to use a helicoil insert to reinstate the thread?. Will that have any negative outcome, using a helicoil? Thanks.
I dont know if they make any kind of repair kit.
You can helicoil it but will need to use hollow screw. The screw size is 12-28 if you can find helicoil kit that size.
I see Jacksonville.. I have a 850 demon with 33 squirters .. it's fine unless I floor it then it studders has a little hickup then clears up. Should I go bigger squirter???
It's possible you could need more squirted, alot has to do with the cam and ignition timing ,the more cam , the more squirted, usually .033 is enough , look at your ignition timing too not enough timing or not coming in quick enough , so many things can cause this ,some times not enough converter , even a weak ignition coil can cause this ,if I new what you had in your engine , compression , cam specs , cu in timing , intake manifold that would help me , make sure zero clearance in acc pump arm , send me so more information and we will do our best .
Top video pal.👍👍👍
Thanks
Does this magic work on all car carbs? I have a Honda Civic EG3 from 1995 with a 1,3l carb engine. The engine runs like a swiss clock but the carb sometimes gets dirty and starts having it`s own mind. Can I do the same to my car?
Most carburetors just need a rebuild kit. They are calibrated for the specific car there made for. I'm not sure what you mean by starts having its own mind.. if you can explain more clearly mabe i can help.
I have a hesitation after shift (standard shift), just normal driving. It doesn’t backfire, honestly I think it’s rich. What can I do about richness. Brand new (refurbished) from Holley. It’s on .30 454, it’s got low end cam for towing. Idle to 4,000 rpm. Straight out of box 2 of the mixture screws all the way in. It’s rich at idle, doesn’t adjust out good. My old 4779 runs better but I wanted electric choke & vacuum secondaries. Float level is right, pump set right, transfer slots right. I’m running factory fuel pump, got a regulator & gauge coming before I send back to holley, but I’d rather fix it. All they going to do is flow it again & it was already supposed to have been LOL. Any suggestions I may try. Thanks
Woody I believe I would send it back to holley , when you see two mixture screws all the way turned in, that's a red flag. If you won't to fix it your self it needs adjustability, changeable air bleeds idle fuel restrictions pv restriction ect. Also need to know the color the plugs are burning, type of distributor mechanical or vacuum advance and mechanical. And if vacuum advance is used is it hooked to manifold vacuum or ported vacuum at carb , there is so much information needed, you decide and I'll help you any way I can , if it has know adjustability I would definitely seed it back to holley. Hope this helps.
I need help brother, I have a Holley 650 and no gas is squirting..happened out of nowhere! I changed the accelerator pump diaphragms, brand new fuel filter… pressure is at seven and still nothing no squirt in the chamber. What do you think it is? Thank you
Usually the check( slash counter weight) under the squirter screw gets stuck, be careful not to let it drop down the intake. If it keeps happening you may have to clean and gently reseat the check/ counter weight using a small punch and small hammer. lol
What about a lean stumble where the throttle is pushed so lightly, in second gear and at around 2000 rpm, that xLr8r pump isn't even being used?
My original ifr in my 650 speed demon double pumper was at 0.033", then I put in a set screw drilled out to 0.026".
Could that do it? It didn't do it before.
Timing is 24 initial, 38 total.
Thanks
The accelerator pump should always squirt unless the check counter weight is not seating , now .026 is not enough usually i run .035.. then make sure you have your transfer slots around .035 . That.should take care of your problem.
@@holleycarbshowtosadvice40y90 Ok thanks, but the ifr was 0.033", too rich at 3000 cruise. I got the cruise afr pretty good now with 28 ifr, and jetting down from 74 to 66. With doing that, Wot is a touch lean at 13.5 afr (primary only), so I will drill the pvcr from 059, to 064".
The nozzle is 35, maybe try the 37, see what happens.
The pump does squirt its all good, but the throttle is pushed so lightly, it might not be enough. If I stab it quicker, it's good..
Jake before you drill your pvcr start by changing your ifr circuit back to .033 to .035 then correct your 3000 cruise with a main jet change and your wot may be ok get your air fuel correct then check your 1300 to to 1800 cruise and check ifr fuel ratio.hope this helps.
I have a hesitation, but its not from the squirter. It's a lean spot because the secondaries are opening too soon. I tried the heaviest and the second to heaviest springs (ive actually trued all the springs) and I still get a slight hesitation before the secondaries open. What else would you try?
I tried putting a small strand of wire in the high speed air bleeds, but it did not help. I've also tried power valves from 5.5 to 10.5. My idle vacuum is about 18 inches.
it's a heavy truck, 6600 pounds, it has a manual transmission with a 4.56 rear end. The engine is a stock 454, they have a very small cam with 195° duration at .050, so it doesn't really turn a lot of rpm's, 4500 max.
Ive tried a 600 and 800 edelbrock, a 600cfm 1850 holley and a 670 street avenger. My timing is at about 13 initial with about 38 total.
Im not sure what to do next. Any help would be appreciated.
What kind of distributor are you using, is it all mechanical or have a vacuum advance , and if so where is your hose hooked to on the carb for the vacuum advance. Which carb are you using now, if it's a 1850 let me know does your secondary diaphram housing use a ball check or a small .045 hole for the vacuum to work the diaphram.
@@holleycarbshowtosadvice40y90 I am using the 670 street avenger right now, im not sure if it has a ball or the small hole.
The distributor has vacuum advance also.
I would like to go back to the 1850. It has the small hole, I do know that.
Ok make sure your distributor vacuum hose is hooked to the metering block which is ported vacuum on most carbs or could be in a different place its according to the carb, you don't won't manifold vacuum. Also if you won't to slow down the secondaries opening use the ball Check housing its ok to switch housing if you have to , alot of people leave the ball out and it will open secondaries early.hope this helps.
@@holleycarbshowtosadvice40y90 yeah, thanks that helps.its nice knowing which one was the best direction to go. We'll see if it fixes it.
Do you have any guesses on if the 670 has the the small hole or not?
I would try to use the sec. diaphram housing with the ball check .
my 4160 Cab on my 390 engine, i had to spray gas into the Carb for the car to start it wasn't spraying when you press gas, , i rebuilded the carb now it's spraying but now i have to press the gas to start the car once i stop pressing gas car turns off, any suggestions please?
Check your gasket between the main body and throttle plate, the wrong gasket can block the idle circuit and cause it not to idle.
Check valve leaking back into the carb and a hesitation upon excelleration.
I thought about the hammer tap but since it was a new Holley I didnt do it. 650 double pump etc.
Now, I still have minor flooding after a warm engine shut down and a hesitation after trying everything else, so next I will try the hammer tap trick.
Thankx for the video and advice.
Hope it helps
My car has a 383 with a 6 barrel configuration. Do you have any videos showing vacuum hose connections to/from the carburetors to the engine? Also, the adjustment of the linkages and return spring placement?
What kind of tri power setup do you have, are the front and rear carburetor vacuum operated , they usually are , it runs primarily off the center carb and the front and rear carbs come in at higher speeds If you have a distributor with a vacuum advance ,you will wont to run your vacuum hose from the distributor to the center holley 2 barrel on the passenger side metering block.hope this helps , if you need more help let me know.
@@holleycarbshowtosadvice40y90
Thanks for the follow-up. I can't tell you much about the power setup, for I bought the car used (translate auction), but it is a '69 Plymouth Roadrunner with a 383 and a Pertronix coil/distributor, which has a vacuum advance. The vacuum connections that I am interested in are the ones from the larger ports on the passenger side of the center carb (one near the top and the one near the bottom). I'm thinking they are to attach to a breather valve (driver side) and/or a PCV valve (passenger side), but which goes to what? The current setup is that the breather valve connects to my air filter (driver side); the lower port from the center carb attaches to the PCV valve; and the shop bored a hole into bottom of the air filter (passenger side) and installed a port and connected a vacuum line from it to the upper port of the center carb (I don't think they should have done that).
It's a bit wordy, but hopefully not confusing. 🤔
@@dogdoc1 I think the "mystery" hose connection that you mention near the end of your comment is probably a float bowl vent plumbed into the air cleaner which is perfectly fine and a good idea.
@@mickangio16
Thanks for your reply, because a garage made a connection from my air cleaner to one of those carburetor ports. Good to know.
The vent probably went to a charcoal canister originally. It could have been left open to unfiltered atmosphere where dust and dirt can make it's way into the bowl but plumbing it to filtered air is a better idea.
My primary jets are 78, secondary 80 , car still hesitates . runner a 4500 prosystem carb. What is the proper jet size from primary to secondary
Is it a two circuit or three circuit and what size cfm, might be best to call pro systems and talk to them, you can come up with a hundred different fuel curves.
I have a question well two actually. The first one is what does it mean if gas shoots out of the fuel bowl vents? And two in your opinion what may be the cause of my car sputtering out once it starts? The car will start but will die unless I keep my foot on the gas but once it heats up the engine is fine. Just can't seem to figure why it does both. Hopefully you can help me out. Thank you and I appreciate your video felt I learned something.
Gas coming out of your vent tubes could mean several things , fuel pressure is high, should be 6psi or less if its high correct that first , also bad or sticking needle and seat , bad float , or bad sealing surface around the needle and seat o ring or the o ring itself , anything restricting the vent can cause it, hope this helps . On your second question I need to know if your carburetor has a choke.
Maybe you can give me a suggestion on jetting for a 780 vacuum sec. It's on a 350 Chevy with.489/.504 Lunati, 185 cc runner ProMaxx heads, Air gap intake, 3000 stall, 3.73 gears. Car ran 13.07 in the quarter with a 600 Edelbrock. I have 70 in the front on the 780 with a 6.5 power valve, 76 in the rear with a power valve plug. Does this sound close?
If you have a air gap dual plane intake, try jetting up at least two sizes on primaries and secondaries see if that helps performance.also keep reading your spark plugs .I Make a 1/8 mile pass then I kill the engine , coast to my pit , pull the plugs and read how they are burning.
Wonderful job, thanks.
Thank you.
Hi of the topic how would you determine the correct power valve size for a ski boat ? I’ve been told boats have a different load so I can’t do the same procedure as a car
Send me your list # off the front of your air horn.
Holley Carbs: How To's & Advice ,40 yrs of exp. sure will do I will drive up next weekend and take a look it’s in storage at the lake Thanks 😊
Excellent video!
Thanks I appreciate it.
How do I know if it's to much fuel or not enough I'm having hesitation on acceleration on my 283sbc
Usually its a lean accelerator pump, with engine off look down your front primaries and while opening the throttle watch your pump squirters they should squirt fuel from the time the throttle moves. If not adjust accelerator pump arm where there is no play.If they squirt fine then change your pump squirter to a larger size, by removing carburetor and look on the side of the squirter, the size is usually marked on the side of the squirter or discharge nizzle. Start off three numbers larger, make sure When you remove the nozzle you dont loose your check valve under your squirter. The reason i told you to remove the carb is if that check valve falls out or you move the throttle the check valve can fall down the intake and damage the engine. Hope this helps
Thanks for sharing
Thank You
Can you explain how air bleed jets work?
Asking for a friend… 🙄
There is alot to air bleeds and I will do a video later, but if you make your air bleed bigger it will lean the mixture, and a smaller air bleed will richen the mixture, there is so much more you need to know, will have to cover the rest in a video. Hope this helps.
@@holleycarbshowtosadvice40y90 -
Does a bigger air jet lean it more on the top end and less on the bottom of rpm.
Look forward to your video. 😎
Thx
Explained clearly novel function and accelerator pump clearance
Thanks
Can i ask. Do you use a check ball in the vac dioframe and why are they their pls Randy
The check ball slows down the opening of the diaphragm, some holleys use a fixed orifice instead of the check ball, then fine tune with your diaphragm springs.
@@holleycarbshowtosadvice40y90 Iv always taken the check ball out, thought they run ok. Is it still better to use them. Do you use them on your carbs Randy.
Sometimes I use the ball checks but mostly use the fixed orifice, and tune from there. Study the vacuum feed passages for the diaphragm. Hope this helps.
I have a question; i have a stock 360 in my d150 and have been driving it for a while, it has had slight dips while cruising but nothing major. I checked the plugs and they where really light so i jetted it up from 71 to 73. Now it bogs while i cruise. I can drive at 1/3 throttle and it bogs/hesitate for a second and gets back up. Also have alot of hesitation while rolling down hill with no throttle, but it has done this all the time. It is a 650 holley 4160 w/rear metering block.
I don't understand your terminology I need more information ., And rolling down hill with your foot off the gas hesitating?
Great video. Thank you.
Your welcome.
Thank you for your wisdom! I owe you a beer if we ever meet!
Good luck Alex , thanks for watching.
Mine was missing. Do i need to take intake off to find it?????
My accelator discharge nozzel had to of went into intake
I don't understand your question please leave me as much detailed information as possible, thanks
@@holleycarbshowtosadvice40y90 Its all good it doesnt have a nozzle on back two barrels
I am having a hesitation off idle, below 2k rpm. It also does it at cruise when im barely on and off the throttle. Should i adjust transfer slot, ifr's or the low speed bleeds? Orange pump cam, although the hesitation is at very light throttle, it spikes lean and hesitates.
Is your accelerator pump discharge nozzles clean and working , next check and see what size the discharge nozzles are , usually an off idle stumble is due to not enough accelerator pump shot, may have to go at lest four sizes bigger. Hope this helps.
@@holleycarbshowtosadvice40y90 its a brand new Quick fuel 670 Brawler. The hesitation is with very light throttle, like driving through a parking lot slowly, just one little spot, it spikes lean and will stay there if i keep that same throttle position.. 31 squirters in it, orange cam.
Alright make sure there is no play in accel. Pump arm and try a .035 nozzle, if that don't work , try a bigger idle fuel restrictor and make sure your float level is adj. properly ,you can also try a smaller idle air bleed both will richen up low speed , as long as this problem is happening before the booster starts flowing. hope this helps. ps make sure your ignition timing is working properly and advancing off idle.
@@holleycarbshowtosadvice40y90 hey thanks for the response! Ill check all you posted.
My opinion- white #218 pump cam THE BEST driving cam.
Do you have a source or a link for tiny drill bits for drilling passages on the carb?
Where I usually get mine is off the snap on truck or matco tool truck , I'm sure any quality tool company would have them., I ask for carburetor drill bits and they usually will sell you the little hand held pin vise to go with the drill bits..
Thank you Randy.
Wayne thanks for watching.
Hey do you have a video on timing??
I have one called dialing in your msd distributor. If you have a specific question let me know. Hope this helps
I love you videos. Thank you for the help.
You are very welcome
What if at 2000 rpm cruise and you step it quick and then it acts like it wants to die maybe it dies for a second until you lift your foot? Could that be the secondaries pump nozzle on a DP?
That's a good possibility , to much pump clearence or blockage at discharge nozzles primary's or secondaries, or needs bigger discharge nozzles, there is so many things to look at , process of elimination don't forget timing and advance, thanks for watching.
If everything checks out ok , either drill your accelerator pump nozzles about .005 larger or change pump nozzles to .005 bigger , this is where having a set of guage pin to size the hole is great to have, the number on the discharge nozzles #25 means its .025 thousandths , note if it's never been drilled before.
Your explanation of the function of the check weight could leave to confusion. What you said was that when the fuel comes up out of the pump that check weight has to stop it, and that's not true. It's when the fuel STOPS coming up out of the pump that the check weight has to close to stop the suction of the pump from pulling the little fuel, and subsequently air (because it's far easier to pull air than it is fuel), back into the pump. It should also be noted, that sometimes it's not a checkweight but a check ball and spring.
Also, if someone is going to measure their squirters, they need to measure BOTH sides, not just one.
I'll have to clarify that on the check valve . On the accelerator pump discharge nozzles that should be just common sense. Have a good day.
thank you very much
Thank you .
It think you should have covered the power valve ,be for going to the squiters ,that's just me and where I would have made sure I had the right power valve 1st ,great video well done
It's very unusual to have a power valve cause a stumble right off idle and it's a lot easier and cheaper to change accel. pump adjustment or discharge nozzle size than to open up the carburetor .
Sir you are the man...thanks. where are you located.?
Jacksonville fl. Thanks.
I'm putting a holley 350 2 barrel on an Aussie 253 ci. Any tips
Sounds like a good combination , maybe a little tuning , I put a 2 barrel motorcraft carb on my son's 258cu.in. straight 6 in his Jeep , I think all I changed was to a leaner set of jets not sure on the cfm size , . You may not have to change anything, let me know if I can help. Thanks for watching.
Good explanation
Thank you
How can I know what Holley I have? I have a double pumper but idk the part number
Should be stamped right on the front of the choke housing.
Yes get the list# off the front of the choke housing , then cross list# number to get cfm size , for instance if list# is 3310-2 its a 750 vacuum secondaries the 2 means second generation.
Will jet size have any affect on off idle stumble?
Not usually , most of the time it will be in the accelerator pump , either pump not squirting or out of ajustment, or not enough pump shot. this is the most common problems.
@@holleycarbshowtosadvice40y90 How can you tell if it's too much fuel getting pumped in there or not enough?!
Fantastic tutorial
Thank you
Just sub'ed great tips thanks gonna rebuild
My Holley 4777-2
Thanks Bruce
Nice add another one to my books.
Thanks
Outstanding 😊
Thanks
Great information
Thanks Bill.
💪 thorough!! Thank you
Thanks for warching.
Loved that!
Thanks Tom.
You didn't mention the accelerator pump cams .
Wrong cam ,worn cam will cause a off idle stumble. One screw change out the accelerator pump cam iv run across people install the wrong cam several times.
Yes I need to do a video on pump cams.
Man Awsome video thanks
Thanks David.
@@holleycarbshowtosadvice40y90 I could use some advice. I built a 468, 454 at .60 over. 10:1 compression with AFR heads. I think I under carbed it with a 750 vac
But lol after breaking in the cam I'm 13 minutes I sucked down almost 5 gal gas.
I think my power valve is off. I'm running the big mother thumper cam. Any suggestions.
@@holleycarbshowtosadvice40y90 also I rebuilt the carb. I blew out the air bleeds one was stuck. I like your advice on the 50 cc and mods for a squirter
Well I’m going to send it back for refund.
I really like to find a 650 classic vacuum & electric choke. Can’t justify buying new for this truck. If you happen to run up on something I’d appreciate a hollar. Thanks Randy for your help🤙
You bet,take care.
Thank You!
Your welcome.
discharge nozzles over size# 40 need the hollow nozzle screw.
Absolutely
Now that was cool.
Thanks.
I'm thinkin this guy knows his onions!
Thanks.
Thanks man
Your welcome.
thank you.
You are very welcome.
I had a 600 holly.It had a stumble, plus bad acceleration on my 351w.I fixed it, with a 750 Quick fuel slayer.Drives like I have 50 more hp at least.I will never use holly again.
Holley owns quick fuel , still a Holley carb.
@@holleycarbshowtosadvice40y90 The design of the slayer is totally different than the holly 600 I had on the motor.Maybe holly bought them out because they knew it was better than there's.The slayer is easy to adjust with more fine tuning capabilities than the old holly 600.All I'm saying is my motor runs a whole bunch better than before.
Now that’s a screwdriver lol
Its special lol