Holley Carb Accelerator Pump Adjustment - Summit Racing Quick Flicks
HTML-код
- Опубликовано: 29 апр 2013
- Does your vehicle sputter at the starting line then take off? Does the engine seem to stumble at the top of the highway on-ramp? Norm discusses how to properly tune a Holley style 4 Barrel Carburetor Accelerator Pump for smooth and consistent launch down the track or onto the highway. www.summitracing.com/redirect?...
Авто/Мото
Hi Ron,
You’re welcome; remember to keep your clearance and to check it at WOT just like you said.
On most Holley four barrel carburetors I would start with the Inlet circuit, then Idle circuit, then the Power Enrichment circuit (power valve). Of the three you mentioned I would dial in the Power Enrichment circuit because it is more black and white or objective in nature.
very helpful, I have a stumble at the beginning, I have just ordered a new nozzle, keep on doing those videos 😉
Really good video. Thanks for posting. A couple of tips from the cheapseats. If you have the old style float bowl with the checkball in the accelerator pump system, get rid of it. The newer style with the umbrella check valve work way better. Also, make sure the pump arm that rides the cam is nice and snug on the hinge. Use a small rubber bushing to help secure it. There should be no play as far as side to side, only up and down. Looking forward to more great videos. Thanks.
New to Holley carbs and you are my new tutor! Thanks!!
Thank you for watching!
I've been watching a bunch of these different tuning / informational videos. They have all been extremely helpful. Thank you Summit
+Dylan Plaeger-Brockway,
Thank you, Dylan! We appreciate the feedback. Please feel free to ask questions.
Excellent! Great help. Eliminated my "bog" and appreciated the detail!
Great video. Very intelligent explanations of the acceleration pump circuit
I have not found any discussions on what the different accelerator pump cams do, and which one to pick for best operation?
Thanks Jonathan! Let us know if you have any questions.
Once all the Primary adjustments are made and the car is driving well, then if you have a stumble when the Secondary opens; change the size of that squirter nozzle.
Helpful info. But, I like how there's a sense of inevitability that you WILL need to spend MORE money (on squirters , jets, and cams) to get it running right on your car.
Great video! Bur I was confused by what seemed to be conflicting info on pump cam positions. It seems to suggest here that position 2 or 3 on the pump cam delivered more fuel than position 1. But Holley's video suggested position 2 or 3 delivered less fuel. Also I wished someone would do a video on what the pump cam colours mean.
Awesome vid, got some good intel going forward on my new carb setup
Hi ehumpy,
Thank you! Let us know if you have any questions. Thanks for watching!
Hi John,
Taking into consideration the description here on the build, the symptom of initial hesitation and knowing that most cams increase their capacity (except the black cam) when going from number 1 to number 2; I would make the move up to a 37 or 40 just to see what happens. It seems to me that what you’re describing is the need for a bigger initial shot to overcome the transition not a longer duration shot. If you go to the 40 be sure that you use the hollow discharge nozzle screw.
Good job Norm, thanks !
another great carb video. thank you
Hi Alex,
Regarding fuel flow in the secondary side; does fuel flow from the secondary accelerator pump squirter or nozzle as the secondary throttle plates begin to open? Does fuel flow from the secondary boosters once the secondary throttle plates are opened? Where is the fuel level in the secondary fuel bowl? Once the engine gets to operating temperature what is the curb idle speed RPM and what is the vacuum reading in inches of mercury? Let me know; I’d like to help.
why are there more videos about tuning 4150 and 4160 holleys instead of the summit 600 street strip carb?
is it possible that i get a bog from rich idle mix when i take off even though pump nozzle is the right size or idle mixture does not matter when i take off thank u
wow cant beat that video.
I have a Holley single barrel carburetor model 1960 in my 1959 ford f-100 I realized the bowl was cracked and bought a remanufactured one and when I put it in and up untill now it bogs down like crazy even if I give it a little gas, but it never did this with the old one, just today I swapped the metering unit and pump diaphragm operating rod and spring with the old one and it still does the same thing any suggestions ? I am about out of ideas of what it could be and anything will help thank you - Ben
Hi John, When you went up from the 35 to the 37 did the hesitation improve, get worse or no change? You may have to move to the 40 to notice the change. Also, I see that you are lean; make sure your fuel delivery and float level is correct and get some fuel in the chamber. Do you have your cam duration at 0.050 in., how much vacuum are you pulling, 4-speed automatic or manual transmission, and what is your curb idle speed? Let me know.
From there I would go to the Accelerator Pump circuit which is more subjective than the Power Enrichment circuit but not as subjective as the Main circuit (jets).
Hi Ron,
Do you have a 30cc pump and housing using a 50cc pump lever? Is this a new 750; if older are you the original owner of the carb? Are you telling me that the spring is stacked solid on the adjustment nut and bolt? Let me know.
Norman, 4150 Mechanical Secondaries,
is there suppose be be a little steel ball undeneath the discharge nossle??.
( im saying way down in the well were the squirter bolts down to.)
the steel ball looks like a little ball bearing..
@6:40 the squirter size doesn't effect the amount of fuel. The pump cam effects the amount of fuel delivered. Squirter size effects for how long it is delivered.
hey norm, you thinks possible to add a Holley 2 barrel to a Harley?
like a 98 cu. with 10 to 1 comp.
kicking around the idea.
larry
Thanks so much for the videos. Very helpful.
Thank you, cobaltn!
I have a 3301-1 holley carb, vac 2daries electric choke, sgl pump, dual feed. pri jets 70, sec jets 76, both pv's are 7.5, #35 acc pump nzl, stock acc pump. This on a 460 ford, med cam, 2"dia headers, 2.8 gears, 4 spd. in a fenderless 31 coupe,What is happening for me is, when adding throttle just above around 1/8th throttle I get a bog then takes off. blipping throttle quickly I get puffing back up the carb tonight i tried moving acc pump cam to #2 and it seemed to help what else should I try
Would be nice to know what these color codes are so I know which one to start with.
What does holly expect? We just start sticking cams in and text it 100 times?
I keep becoming less and less of a holly fan.
if a carb cranks up an runs and then shuts down like its out of gas can you tell me whar may b the cause
That's what it was... a 50cc on a 30cc pump housing... thanks!
Also... when tuning the Power Valve, Metering Jets & "shooters" what do you recommend changing first? Thanks!
Help figure my carb out..1985 ford mustang gt....it runs great almost perfect...car is a stick...but when u drive...i lose power between 1 to 2 and 1/ 2 g rpm this carb has been on the car for awhile...no gas leaks new fuel pump manuel took the filter off.. still runs great....just cant drive the car....its a 600 holly
Very helpful 😀👍 thank you
I'm having issues with my Holly 500 CFM Avenger Marine carburetor it's tomblin and sometimes popping back off idle 28 square tear jet does not look like it's spraying all the way with pink plastic cam the motors of 5.7L 2 barrel
very well done.
Thank you for watching!
My very old Holley H.P. book said pos.1 is a lot of fuel quickly whereas pos.#2 is the same amount of fuel over a longer time.Stick ,Auto trans.
my 700cfm 4150 doesnt seem to be shooting any fuel from the secondaries...bad diaphragm or needle/seat? faulty check valve possibly? No obvious leaks from the accel pump and the fuel level is adjusted properly.
excellent videos - especially the theory side of things to understand why. Could do with an exploded diagram or 'map' of the carb to give an overall view and how things interact. Still brilliant video though....
great video really helpful
rezajahanshahi ,
Thank you for watching!
Norm, I'm currently trying to adjust mine on a Holley 750 double pump (out of the car) and no matter what I do or what direction I turn the screw on top of the arm spring the 15 thou feeler gauge will not slip in or if it does it's still very tight and this is at WOT..... What am I doing wrong?
all new plugs, wires, pertronics system, and flamethrower coil.... and plugs are showing a lean(light grey) in color...jets in carb are 70 in primary and 76 in 2ndaries. I have a set of 72,74 78, and 80's, to work with,,, also noticed no ball under accelerator nozzle. #37 with hollow screw is in...still seems slight hesitation ( at well above idle rpm maybe at 1000rpm? tach doesnt work so not sure)
Nice tutorial!
I will assume that your ignition system is in good shape and that you are reading your plugs for air/fuel. Let me know.
Do u have a tutorial covering the Holley 3160 carbs ???
Hello. I checked my to see if I have a .015 gap between pump arm and diaphragm, but there was no gap! I kept tightening the screws together until the red spring was fully compressed and I still can't get shim between them. I started it and it bogged on throttle worse than usual. So then I turned the screws back apart and expanded the springs as far as they would allow and it didn't bog like it did. So it stumbled the more I compressed the spring. Why can't I get this gap and why is it so important?? PLEASE HELP!!!
BTW, I have a 4160 vacuum secondary that always bogged on WOT from a stop. I will try a larger squirter.
+dbytor ,
Did you see this video? ruclips.net/video/w3F3ssOb8lg/видео.html
Let us know if you still have questions after watching this video. Thanks for watching!
I get sometimes get a lean backfire, or a stumble idle to wot ; both through the carb. So far ive went from a .31 nozzle to a .35. It has seemed to help somewhat. What would cause that?
Per Norn, he would continue to increase the nozzle size since it helped and to make sure he maintains the .010” clearance at WOT.
Hi John- Great video, I have a 4150 and its only stumbling a bit as I open up the secondary's quickly and as the RPMS get past 6 , then it seams to clears out. If i slowly lean into the throttle all the way up, it seams better. Bottom line , if I smash it , its lazy/stumble and than opens up most of the times. I recently took the 76 jets out for 73 in the secondary's. Seamed to get a little better. a slight sulfur smell also after .70 Camaro-355/ 202 heads and 3:73 rear. Should I go up in squirter size?
Hi Ken, we will need some additional information from you.
We need to know the list number of the carburetor. What camshaft is being used? If an automatic, what torque converter? What kind of vacuum is the motor producing? Idle rpm
I have the holley 4150 570cfm and sudenly when i floor from stop to full throttle..the carburator backfires very much!what is the problem??i need bigger nozzles or different pump cam!the carburetor is all original from holley i haven't change anything on it!
steliosz28,
The first place to start is
sizing the power valve properly for the needs of the motor based on a manifold
vacuum signal. From there you would change the squirter nozzle size and then a
pump cam. We carry all those tuning parts in stock! Give us a call, we
can help you out. 1-330-630-0240.
Thanks for watching!
Crap what me having trouble with is the damn accelerator pump itself. The diaphragm keeps sticking and the spring wont push it back.
Great video, I have a holley dp 750 when you change accelarator squirter for primary and secondary plates do they have to be the same size or it doesnt matter. Thank you for thoughts.
Hi *****,
The squirter nozzles do not need to be the same size. In fact, it is quite normal for them to be different sizes. Trial & error will need to be used to figure the correct sizes for your driving habits and proper reaction at the track.
Summit Racing trial and error? I saw the price on those nozzles were $21 each. How much to buy them all and do this expensive trial and error thing? All this trial and error stuff has done nothing but piss me off and make me hate holley more then ever.
One thing I have learn thru out all this is if you have a light car and depending on gear ratio vehicle is going to require big nozzels and smaller nozzels for heavy vehicle. Something to keep in mind
I would have liked to hear more about the cams and their application. There are three holes in the throttle arm and three holes in my pink cam. That's 9 positions. What happens as I go from hole to hole? Thank you.
Leo M. Mara,
Those holes speed up or slow down pump arm actuation. Each cam that Holley offers in their assortment kit has a different ramp or profile to give different results. This shape controls the timing of the shot. A gently sloping ramp will spread the pump action over a longer period of time. A steep rise in a ramp shape will give a fast, heavy fuel shot right off idle.
Thank you. I was aware of that. I was hoping for a guide or matrix to tell me, for example, what going from hole one to hole two in the throttle arm or cam would do and visa versa.
Leo M. Mara Good luck with that. I printed out a chart that showed each ones curve. It did not however show whhow each hole modified each curve. I tried all the cams, all the holes, something like 18 all togeather, and ran out over a quarter tank of gas. This POS holly still not right. Many I tried twice trying to find the one that gave the least problem. Right now I am about to begin the search for another carb. I tried the holly thing years ago and ended up putting an Edelbrock on it and ran perfectly. IMO holly is junk unless you have a dyno shop and all the necessary stuff to tune it with. $300 for it to be dyno tuned, and that would buy another carb. None of the auto parts stors stock the holly adjustment parts, and they don't come with the carb. The accelerater pump jet is $21 EACH. How do I know which one I might need? Buy them all and test? And how much will that cost? How many different combinations are there? Dozens. Then there are metering blocks and power valves I havent even messed with yet. Do your self a favor and sell the holly and go with something less adjustable.
Summit Racing Thank you. I was aware of that. Does Holley or anyone produce the guide I asked about?
just off idle the car in Neutral, maybe around %20 throttle , engine starts to pop and crack? its a holly 4150 600 hp ultra
Hi 80thill,
We would be happy to help! However, we have several questions for you. We think it would be best if you called our tech line. 1-330-630-0240. We look forward to your call. Thank you for watching!
How do you install the umbrella check valve correctly? When I put it in I am not sure if it will stay in the correct position.
Hi Casey Skipper,
The round flat face of the Umbrella check faces the accelerator pump diaphragm and spring. The stem of the umbrella gets pulled up into the fuel bowl. This is of course providing you don’t have an older carb that had the captured check ball in the fuel bowl. Let us know if you have any additional questions. Thanks for watching!
+Summit Racing WHat the best way to pull it through with out snapping off the tit,
Hi Norm, Automatic Foot braking , Drag racing, I start at 2,000 ( 3500 lb car ) and find a stall nose over bog, Im using Summit Carb,650VS, Seems I am running outa fuel from cam, Holley doesnt include the cam/number position to match which cam does what, I need partial cam squirt upon loading , than full volume when I nail WOT at "go" , more claifing of profiles of Cams and nozzles
Sirs, how much psi is required for a 4 barrel carburetor?
Hi Albert,
Depends on the carb. Edelbrock's are around 4-6 and Holley is higher at 5-7
I have a Holley 850dp and had terrible off idle hesitation and bogging. I bought a cam kit with the assorted cams and it looks like only a couple cams can actually be used with the 50cc pumps. Is this the case? I have dual 50cc pumps and 35 nozzles on mine.. Also do the cams go in facing a certain direction ( numbers out towards the fenders or can they be flipped over)
Hi foxforma,
While all cams should be usable, only a few will have any results for you. Please take a look at this video and resume experimentation.
Accelerator Pump Cam Selection And Installation On Holley Carbs
I am running #37 in bot h the primary and secondary .
Hi Ken, we still need some additional information from you. Can you give us a call? 1-800-230-3030 or you can email us: help.summitracing.com/app/ask
Will that cause a dead peddle effect
4160 holly
But I wanted a pretty purple pump cam.
Machine one.
great explanation for a dunce at tuning carburetors.
This holly is pissing me off. Its brand new. Any one want to trade for a good quadrajet or Edelbrock?
#countryboycansurvive same shit with my holley
good lord dude! get to the freakin point already! some of of have adhd....