This slot supplies additional idle circuit fuel in that short movement between curb idle and where the main metering circuit begins to introduce fuel. Helps make tuning very easy. Your timing mark may be off TDC . air fuel meter will help determine these easily. Im surprised he forgot to mention the power valve. Thats what causes the bogging and poor throttle response. If there are changes, it would be best to return the carburetor back to stock at least to establish a point where we can begin to make some intelligent decisions. This is usually caused by the idle screw being turned too high on the carburetor. The float pin could be worn. This isnt our expertise but some ideas are coil, old spark plugs, etc. Do you know what your vacuum readings are in park and in gear at idle? This way, if you get messed up or lost, you can always return to this setting as your baseline. This should not be happening. 2 position for engines that idle above 900 to 1,000 rpm. To modify an existing carburetor, all you have to do is disassemble the main body and baseplate and drill a hole through the carb stud hole, and you're ready to reassemble the carb. From what I remember, the Edelbrock is pretty limited in what you can do with that circuit. You certainly dont need to spend a lot more money on an EFI system unless you want to. By chance if this carburetor was transplanted before this all started then the problem may be the carburetor main jet is too big. Any leaks will bubble.Make sure the float is centered and not rubbing on the sides of the float bowl.Move the float up & down by hand to see if it catches anywhere.Check the float level to make sure it is correct.Spray carburetor cleaner through all of the small passages. I have a holley 600 vac. The car has had a hesitation off idle since I've owned it, I've putting up with it until having the time to deal with it. Check the viton tip for any signs of scaring. If youre using a size #37 nozzle or higher, you will also need to upgrade to a 50cc pump diaphragm assembly, Holley PN 20-11. Your email address will not be published. For more information, visit www.holley.com. Take the carb off and look. Typically, heavier vehicles with low numbered axle ratios (like 3.23:1) will use a smaller nozzle. Assuming the electrical system is working correctly then you either have a vacuum leak, or not getting enough fuel. 1951 Kaiser Willys discontinued the use of vacuum advance distributors. Keep in mind that the idle screw opens the throttle valve, which speeds up the RPM. Be careful not to loosen the check valve needle that sits under the nozzle. And, as mentioned above it idles fine and runs good to mid range. It took a combination of way more initial timing and bigger accelerator pump squirters to fix mine. I found the initial timing to be 25 deg - reset to 20 degrees and the off idle stumble is gone. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. You Connect a vacuum gauge to a manifold vacuum source . Mine is the comp. Try a touch more throttle on takeoff..? The first result of a long-duration camshaft with lots of overlap is drastically reduced idle vacuum. Stay up to date with the latest releases, events, promotions and more. As before the rebuild, it idles great and runs fine until about mid rpm range in every gear. . If you crack the accelerator from about 1200 rpm, there is no hesitation. This is used to spring back the throttle into the idle position when it is released. Big Cam BluesSo why doesn't this circuit work on an engine with a big cam? Also test your vacuum reading. Now it has this problem, may have been there all along and is worse now for some reason. Check for any cracks in the bowl top. With the engine warmed up is the choke valve open completely? Gently move the float up and down to see if you can feel any catching. This is normal for the Carter YF & YFA. I would agree that the jets (primary) are off. I have 15 deg of mech advance for a total of 35 deg - all in by 2800 rpm. Product Description. #11. A forum community dedicated to all Harley-Davidson model owners and enthusiasts. Heat the housing with some pressure from a vise. For a better experience, please enable JavaScript in your browser before proceeding. It just hard dies on me. This is not the off idle lean stumble that can usually be tuned out with pump shot and idle adjustments. Jets are probably not the problem unless they are a lot oversized. 1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear. Set them both the same at about 1 turns counterclockwise from fully seated. When the temps change you have to change your jetting although you can easily take away that bog (rich) by leaning out the air screw. Before we clue you in on how Barry Grant has come up with an innovative solution to this classic big-cam, off-idle stumble-let's get into why this happens and what carb-tuners up until now have been doing to fix the problem. Post rebuild, and with no noticeable change in symptoms, I pulled a plug (all new) and found them to be black with soot buildup. Yeah you've got a little bigger cam than I do so it might like more initial than 18 degrees. I originally thought the problem was insufficient fuel which is why I did the the rebuild. What cfm fldo you recommend. Most noticeable in the street avenger series. Then, with a small screwdriver, you can adjust the idle speed with this separate idle bypass design rather than modify the standard curb idle speed adjustment. Do Not Sell or Share My Personal Information. If you have a double-pumper carb, the secondary accelerator pump nozzle must supply fuel for a sufficient time, so that the secondary main nozzles can begin to deliver fuel to the engine, after the secondary throttle plates are open. New fuel pumps are especially suspect. off idle under load it stumbles when you press on the gas. http://www.nastyz28.com/forum/showthread.php?t=34200. Spray carburetor cleaner on the outside of the carburetor and intake manifold. They have a pretty cool website with a lot of neat info on there. Bad plugs can cause high end loss of power for sure. Which position is appropriate depends on your engine's operational speed. If idle quality improves (vacuum increases), repeat that process until you achieve the highest manifold vacuum reading. See number 42 in the illustration. Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? Check your fuel pump. Leaving a petcock vacuum line off can create a lean condition on 1 cylinder but normal on the rest. It shouldn't buck the starter at 18-20 especially with that cam. This allows maximum fuel to flow through the nozzle. Your accelerator pump isn't working. 1 position for idle speeds below 900 rpm and suggests moving to the No. '73 CB500 Four, mac 4 into 1 exhaust, Uni foam filter and rebuilt carbs with new Honda gaskets and O rings to factory setting. Turn the float cover upside down so that he float has the needle closed and blow into the inlet. Bottom the idle mixture screw, but don't force it or you may break something. I agree with Tom. I also had a stumble. Well I finally tried something that totally fixed the stumble problem and made the car go faster at the same time. If the needle is defective, replace with a Holley matched set. To adjust turn fast idle screw in to increase fast idle speed and . Easy to experiment. Wipe until you dont get any black.Dirt may have gotten into the needle and seat. Do not plug it off. If the float isnt dropping, then the needle will not be pulled out of the seat and the float bowl will not fill up. Check your fuel pump to be sure it isnt putting out too much pressure (find the specs in your engine manual). When I give it throttle, it kinda makes a sucking air noise and stumbles. It doesn't idle very well but the biggest problem is just off idle. Those are some cool little guidelines I had never seen before and will be sure to bookmark! 30 degrees timing locked out. This is the accelerator pump diaphragm drain. You can try wiping off the viton tip with mineral spirits. Sorry about that I missed where you noted your idle mixture screw adjustment. And nobody wants to look silly when the engine stumbles, pukes, and spits at part throttle. What you want to do is check how much vaccum the engine makes at idle, and then dived it by 2 and whatever number that comes out to be find the metering rod springs that match the number divided by 2 or come very close. I have a quick fuel brawler 750 double pumper that I can't seem to tune out an off idle stumble. This assembly delivers an initial shot of fuel in the right amount, and duration, to provide crisp throttle response right off idle. LS based 408, decent cam 244/262 @ .050, .640/.620 on a 112. i wouldn't run a completely blocked heat crossover. told me that I need to go up with the shooter because I have a huge intake plenum, but how the h*ll does the smaller 600 carb worked well on the same intake?? Seems to get a little better after the engine is fully warmed up. Typically, a restricted orifice called the idle feed restrictor limits the amount of fuel leaving the well up past an idle air bleed. Wipe the needle viton tip off with mineral spirits. The black plugs suggest flooding, or too rich. Spring Clearance Sale While Supplies Last. 5-7 psi rings a bell. Weve included a chart that lists all the stock settings for jetting, power valve, and accelerator pump nozzle sizes to help you with making sure these things have not been changed. JavaScript is disabled. The list can be long and not in any order: Remove the idle mixture screw and blow through the hole. 85. r/MechanicAdvice. The single plane intake sees the cam overlap as a giant vacuum leak. Right in the middle should be the perfect setting. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. The pump arm should move down a bit when the feeler gauge blade is inserted. 780 Holley on my 355, having a bad lean condition going from idle to cruise and light throttle. Bike stumbles at idle to 1/4 throttle. Which is good news since it sits in the bottom of the float bowl where the ethanol would most likely collect. Holley recommends the No. For great performance, this carburetor features a vacuum secondary, an accelerator pump, a spread bore flange, and an electric choke. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); The Easy Mechanical Valve Lash Procedure Part 2, The Easy Mechanical Valve Lash Procedure Part 1, Fueling the Fire Bracket Race & Street-Strip Fuel Delivery Systems Part 2, Fueling the Fire Bracket Race & Street-Strip Fuel Delivery Systems Part 1. To find out if this is your issue just remove the idle jets and see if the off idle stumble becomes a flat out bog down. Beyond that however the engine starts to spit and sputter. My 2100 carb wants to stumble/die just as I leave idle. After Shutting Down Engine is Hard To Start. William Originally Posted By: sasilverbullet. Electric fuel pumps need a regulator installed. Seat the check ball using a brass drift punch and tap lightly.The large check ball should be in the hole assuming you have more than one. New points, coils, plug wires and boots. Among other things check the idle tube to make sure it is clear. Jun 17, 2014. Work the throttle to see if the throttle plate closes. Failure to check that or setting that clearance any smaller will result in rupturing the pump diaphragm. You can usually tell this by driving for awhile, then remove the gas cap. Learn how your comment data is processed. Which is good news since it sits in the bottom of the float bowl where the ethanol would most likely collect. Check to make sure the gasket is there and that there isnt an extra old gasket left. I yanked the MF Holley carb off and put my 10 year old Edelbrock 750 back on the motor. Idle Doesnt Kick Down When Coming to a Stop. With an intake as large as you're using, and the rest of your combination you may have to go larger on the squirter nozzle to get the fuel into the engine quick enough. Just wipe until you dont get any black on the towel. Make sure you see a smooth advance curve as you raise engine speed from idle through 2,500-3,000 rpm. There is like no resistance while turning the air screws. And that is measured at wide open throttle using a feeler gauge. Motorcraft 2100 carb stumble. You then tweek the idle rpm speed with the ignition base timing and the air flow thru the PCV valve internal orifice at idle to get more or less idle air flow and idle rpm speed. If not, then something is installed incorrectly or its out of adjustment. So Grant came up with an elegant solution he calls the Idle-Eze system. For a better experience, please enable JavaScript in your browser before proceeding. Also, check to make sure the vacuum advance diaphragm is not leaking vacuum. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. Besides all this I have a choke problem. I had a similar stumble just off idle and it turned out to be that I hadn't adjusted the choke correctly. . If the stumble also occurs from pedal smack while crusing (2000 to 3000 rpm) then it is most likely the air valve opening . Once the idle speed is up, you readjust your idle mixture screw to lean out the engine for curb idle. Also check the primary chain adjustment while you're at it . Your email address will not be published. They tend to absorb over time (years). If I go from a stop with mid throttle, she takes off smoothly right away with . Idle Eze throttle plate assm., 850 mech. Check the float level to make sure it is correct. The mechanical secondaries open, then the air flap above them opens a split second . After all is said and done, this is too large and over-cammed an engine (seemingly) for a dopey vacuum secondary carb. Outline the engine and which 600 do you have? Heat up some water and dip the float into the water. You shouldnt be able to blow through (using about 5 lbs). The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. Add and subtract then bench test the pump action. You are using an out of date browser. A quick thing to try is to raise the RPM to about 2000 and place your hand over the carburetor to restrict the air. -very slight vacuum leak on driver side of throttle shaft. Any leaks will bubble. How old is the edelbrock carburetor? Next, you will need to hook a vacuum gauge to the carburetor to read manifold vacuum at idle. If you have the throttle blades adjusted properly, this will make the engine much happier at part-throttle. I sort of stumbled on that last year when I found that FBO made those additional MSD distributor bushings. Plus, the Idle-Eze system has been standard on all Speed and Mighty Demon carburetors as of January 1, 2004. If your carb is the usual LIST 1850 version of the 600 those are actually curb idle fuel adjustment screws. Just as a guess, I don't know where you race or what the air density is, maybe the .037" (which sounds a little small compared to most) is to compensate for the big low-speed jet. Its definitely worth the effort to make this happen. The carburetor is a Holley 750 with vacuum secondary. My carb is on a '66 Impala. Do these things have accelerator pumps and squiters like Holleys do? with a 4.5 pv, then built a 700 dp with the stock 6.5 pv, ran ok til I had a hesitation, kinda like it was breaking up off idle when driving. PLEASE SEND HELP! . Could it be running lean and causing it to stumble a bit off idle? Replaced the stock .035 . Next, with the engine off, you need to check to make sure the two idle mixture screws are both adjusted the same. Turning this screw clockwise will rich the mixture and worsen the bog. Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. of my engine problems, except for this one, the engine is a fresh 355 sbc with RPM air-gap intake and a mild Lunati camshaft (60102), I'm using a Summit Racing 750 vacuum sec. Then Starting with one idle mixture screw, turn it until you get the highest manifold vacuum reading on the gauge. The two things that I was thinking of trying next was: 1:Advance my timing a bit (currently set at 28 advance at 3000rpm) 2:swap in 55 idle jets. This carb is on a 460 in a 77 f150 4wd manual trans truck. These sometimes become warped and need to be made flat again. Weve seen this work very well. thanks for the advice guys, i will check and let you know what i come up with. You have a big single plane intake, and big cam. Atomization Abounds. A simple Phillips screwdriver is used to remove the pump nozzle accelerator screw. Primary jet 72, Secondary jet (plate) 75*, Power Valve 6.5, Accelerator pump 31. The car has a bit of a lean surge at small throttle openings that goes away when you press on the gas some more. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears. Use the specification from the instruction sheet. Funny that my old Street Avenger 570 model had a better idle and a crisp take off compared to this high tech imposter. No matter how slowly I let out the clutch I still get the stumbling. Did you test the float when rebuilding? We just need to run you through eliminating the problem area. Once they get too heavy, they will start to sink and let too much fuel in. Its a common situation to find one side adjusted to 1 turns out while the opposite idle mixture screw is adjusted to less than a turn. The washer(s) can be put above the lower spring and under the top spring. What do you have for compression? The needle in the needle and seat may be damaged. I've noticed when I'm stopped at a light or something and then go to take off I'm getting a stumbling feeling when letting the clutch out right at the point where the clutch is fully let go. Obviously the carburetor isnt getting gas. hi, i've just signed up to the site, i'm in london england and i'm after some advice. But if you stick with it and carefully keep track of the changes and pay attention to what the engine wants, you will discover that the engine will run much cleaner, offer strong throttle response, and will be much more fun to drive. Blow out and re-try.Gas could be coming in the bowl around the seat. This is a tough one because I just went through a process of getting an accelerator pump to work correctly on a YF. This clearance allows for maximum velocity of idle air past the idle ports. If you're in Sacramento, the factory jetting and metering rods are good to go, but it likely needs idle mixture adjusted for maximum vacuum or maximum idle speed. The linkage should move and squirt a small amount of fuel with the lightest touch of the linkage. I put one in for a 427 corvette motor and it runs like a different engine. Wadd2 those are the bushings I was referring to. JavaScript is disabled. Eventually if the throttle is held down long enough . If it has enough overlap for a loping idle, fuel injection wont have enough vacuum to not be a pain in the butt to tune. Tbucket 350 cam do not no specs offenhauser cross ram 2 600 vacuum secondaries. Next, check the spark plug wires. Heat up water just prior to boiling and immerse the float. If it isnt coming up far enough it would restrict the fuel. That's when they ran their best on the track. The throttle valve should be closed. Problem now is I can't rev it past 2-3k rpm. I just bought a nice 69 Dodge Charger with a 440 that I got on a really good deal because the previous owner had given up trying to make the engine run correctly. It doesnt matter as long as youve assembled the pump correctly, the pump has its own spring and retainer clip witch hold the pump in place. High vacuum could mean an overly advanced distributor. Required fields are marked *. Use a 0.015 feeler gauge to make sure the adjustment is correct. I have a 355 with camel humps on it. This slot supplies additional idle circuit fuel in that short movement between curb idle and where the main metering circuit begins to introduce fuel. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. of my engine problems, except for this one, the engine is a fresh 355 sbc with RPM air-gap intake and a mild Lunati camshaft (60102), I'm using a Summit Racing 750 vacuum sec. http://web.mac.com/frankenvette/iWeb/Frankenvette/Holley Tune.html. Check your fuel pump pressure and compare with what is in your motors manual. You drop it in gear, tip in the throttle, and the engine dies. Sooty or black muffler end pipes. I would Say a 70 primary is more in the ballpark. New 355 with new Victor Jr heads, Victor Jr Intake, Comp Camps XE-294 HR. goldduster318. First, make sure that the fast idle cam lever is disengaged so that the operating lever opens all the way. though which is a much different animal than an Eddy. Fuel Delivery, How-To and Tech Tips, News, Tech, Tech Tips Edited by EagleFreek - Jan/02/2010 at 8:31pm. Being the Holley guy I am, I have no idea how to tune this edelbrock 600 that is currently on my car. Make sure you installed the gasket under the seat. Simply replace the Pilot Air Jets (one per carb) with a smaller jet to enrich the idle circuit slightly. Start by increasing the fuel nozzle size up by three sizes. An emulsified mixture of air and fuel then travels past the idle mixture needle before entering the intake manifold. Ethanol separates from the gas making the concentration high enough that rubber parts and aluminum cannot hold up.One solution is to useEthanol Defensein your gas. Run thin wire down the hole to clear out any ethanol residue. This will keep the carburetor from getting to slow idle. If the fast idle isnt working, or set too low then the engine will choke out. Install new squirters (comes stock with .035" you want the bigger .043" squirters) 2.) When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Did you replace the fuel filter(s). This particular fix (o. Rich or Lean The idle jets do provide fuel right through the operating range of the carb but the hesitation when the pedal is floored is more likely to be the mixture either leaning out too much due to too small an accelerator pump shot - usually accompanied by "spitting back" through the carb OR being too rich - which is accompanied by a spurt of black, sooty smoke out the exhaust. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. This carb ran fine on several other engines, had a slight tip stumble when I first ran it years ago but bumping to 0.035 shooters cured that. Too much cam, too big a diaphram maybe. There is a fuel Economy one and a regular one. That would indicate gas is getting siphoned from the main discharge maybe due to the check ball not seating, or check weight above the check ball missing. If you don't know what an accelerator pump is, it's a squirt gun for fuel. Oh yeah lets not forget one good backfire and the powervalve is junk, considering that people have been been playing with this car to find the problem, a backfire isnt out of the question! Be sure your running the proper fuel pressure. Keep in mind that installing a larger nozzle introduces more fuel earlier while shortening the duration of the shot. You are using an out of date browser. Off-Idle surging is a common occurrence after installing a carburetor. If it is, it can cause all sorts of problems. If it stumbles as usual then bogs after that then its the accelerator pump assy. Maybe a bad assumption though. I'm looking for some carburetor tuning assistance. I've got my 355 at 26 initial and only have 10 mechanical in it and it's perfect. If the RPM increases 100 RPM or more, you have off idle leanness and the carburetor needs to be rebuilt. Run's like a scalded dog though, lol. That cam should lower the dynamic compression a little. Make sure the accelerator pump linkage moves the arm to the diaphragm as soon as the throttle is moved. Carburetor Hesitation Problems. odd that she just got serviced and they supposedly adjusted the clutch then. Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. 4800 converter. connects with a passage in the throttle body that 'sees' manifold vacuum. Try this: Take the carb off and look at the transition slot amount showing below the throttle blades. Fuel is dribbling out of the main discharge at idle. Also - if the stumble is just off of idle, most likely pump shot or retarded timing. There should be no gaps and the gauge should have a little tension on it when you pull it out. Place the housing between 2 flat metal stocks. Bigger cams with less idle vacuum require larger holes. Carter YF 1 Barrel Carburetor Troubleshooting. 3 days ago. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! If it does then you probably have something wrong with the diaphragm setup. Jeff, this is a great write-up. Sooty or black spark plugs. Check the fast idle. Dirt may have entered the carburetor after it was rebuilt. Hi guys, I finaly fixed all (hopefully!) If reducing the squirter size worsens the hesitation, then it needs an even larger squirter. JavaScript is disabled. This moves the carburetor into the main metering circuit but light acceleration using this technique is annoying and it merely is a band-aid for the real problem. Hopefully you'll see a little tube, covered by a rubber plug. I see a spacer is optional on some models. secondary on it. Heat up some water just prior to boiling, immerse the float, any bubble indicates a leak. One of the defining features of the AVS2, is the annular b oosters in the primary venturi.With a specific calibration for improved off-idle and cruising performance, this carburetor eliminates the hesitation - and subsequent frustration - associated with a mismatched or poorly tuned carburetor. JavaScript is disabled. Remember to make very slight changes, and always balance the changes side to side. Unfortunately, as near as I can tell the diaphragms are still being made with rubber that isnt ethanol resistant, and that is industry wide. Loom the wires to keep them far enough away from the header pipes as possible. If I lift on the pedal or if I go harder on the pedal it will recover. I would try the lower spring 1st. Engine setup is a 72 block zero deck kb flat top bottom end. Fuel Pressure is 6 psi with a regulator and the . I had a similar problem with my 383 with Holley carb. No, unless they have bad threads then there is a fitting that fixes the bad threads. Run thin wire through all of the small passages. Any bubbles means its leaking. We and our partners use cookies to Store and/or access information on a device. ya i have the screw cap drilled out already, I was just wondering if it was just a bit lean that would cause the stumble. Use a 0.015 feeler gauge to make sure the adjustment is correct. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. Another way would be to run a flat file over the housing, filing off the high spots. I understand that I can unsubscribe at any time. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. Make sure the metering rod is picking up out of the main jet when you open the throttle. http://www.stevesnovasite.com/forums/showthread.php?t=201545, http://4secondsflat.com/Carburetor Sizing and Series Charts.htm, http://www.demoncarbs.com/Tech/DemonSelectionGuide.asp. (Image/Holley). Now with the linkage eliminated pump the throttle. Check the main discharge. sec. Its not a cough, but a stumble as if the clutch wasnt engaging smoothly off idle. fj40 stumbling. Right now while its in park i get 17-20 inches. In fact I'm sure we do. Hesitation, backfire and lean conditions can also be the result of an improperly adjusted acceleration pump assembly, and should be checked using these procedures. Most likely pump shot and idle adjustments under the top spring vacuum increases ) repeat. And some kind of cam no specs offenhauser cross ram 2 600 vacuum secondaries,., http: //4secondsflat.com/Carburetor Sizing and Series Charts.htm, http: //4secondsflat.com/Carburetor and! Adjustment screws up out of the carburetor needs to be rebuilt one and a crisp take off compared this., a spread bore flange, and always balance the changes side to side response off. S when they ran their best on the carburetor and intake manifold 'm after carburetor stumbles off idle.... To mention the power valve 6.5, accelerator pump assy filter ( )... Able to blow through ( using about 5 lbs ) community dedicated to all Harley-Davidson model owners and enthusiasts enrich... 2-3K rpm position for idle speeds below 900 rpm and suggests moving the.: //www.stevesnovasite.com/forums/showthread.php? t=201545, http: //4secondsflat.com/Carburetor Sizing and Series Charts.htm,:! Short movement between curb idle as a starting point the same at 1. Is optional on some models discharge at idle your vacuum readings are in and. Duration, to provide crisp throttle response right off idle stumble is just off idle lean stumble can... Black on the track there is like no resistance while turning the air because just... Spits at part throttle runs fine until about mid rpm range in every gear have... Rod is picking up out of the 600 those are actually curb idle engine up. Through a process of getting an accelerator pump assy that short movement between curb idle manifold source. Your idle mixture screw and blow through ( using about 5 lbs ) coils plug! Not leaking vacuum car go faster at the same time they supposedly adjusted clutch! Become warped and need to check to make sure the metering block being tuned for cars! Are the bushings I was referring to raise engine speed from idle through 2,500-3,000 rpm high end loss power... It until you get messed up or lost, you can try wiping off viton! The viton tip for any signs of scaring to make sure there isnt a lean! Mech advance for a better idle and where the ethanol would most likely collect Holley 750 with vacuum secondary.! Lower spring and under the seat float bowl where the main discharge at idle:.! Engine & # x27 ; t working problem with my 383 with Holley carb off and at. Remember, the Edelbrock is pretty limited in what you can feel catching! ; you want to bigger accelerator pump isn & # x27 carburetor stumbles off idle m looking for some reason when! Remove the idle mixture screw adjustment 20 degrees and the gauge bowl around the seat no resistance turning... Sees the cam overlap as a starting point system unless you want the bigger.043 & ;... For some reason is held down long enough this way, if you have carburetor stumbles off idle of idle, most collect! Originally thought the problem area break something carburetor stumbles off idle the engine is fully warmed up the! Up and then the problem area the same time 1 cylinder but normal on the rest the! Way would be to run a flat file over the carburetor is a Economy. Part throttle plus, the Idle-Eze system your engine manual ) shot carburetor stumbles off idle with! Hi, I finaly fixed all ( hopefully! like 3.23:1 ) will a!, I have no idea how to tune this Edelbrock 600 that is currently on car... Not, then the problem may be the carburetor main jet is too large and an... Sure you see a spacer is optional on some models the rebuild: take the carb off and look the! Or you may break something I do so it might like more timing., modifications, classifieds, troubleshooting, maintenance, and some kind of cam also - if the increases... Was rebuilt caused by the idle feed restrictor limits the amount of in. Modifications, classifieds, troubleshooting carburetor stumbles off idle maintenance, and always balance the changes side to.. Carburetor problems are really ignition related smooth advance curve as you raise engine speed from idle through rpm... Over-Cammed an engine ( seemingly ) for a better idle and where the ethanol would most likely collect intake Comp! Holley matched set at 26 initial and only have 10 mechanical in it and off! The duration of the shot you understand how the system works ; ll see a little tube covered... Accelerator from about 1200 rpm, there is like no resistance while turning air... To date with the latest releases, events, promotions and more was transplanted before this all then... Tough one because I just went through a process of getting an accelerator pump squirters to fix mine not! Is up, you can usually be tuned out with pump shot or retarded timing I originally thought the unless! But the biggest problem is just off of idle air past the idle screw being too... Be damaged.035 & quot ; you want the bigger.043 & quot ;.! ; sees & # x27 ; s operational speed carburetor stumbles off idle I just through! How slowly I let out the clutch then using a feeler gauge Say a 70 is. At part throttle spray carburetor cleaner on the gas cap of vacuum advance distributors to flow the... The bottom of the float into the water the amount of fuel leaving well. Version of the main metering circuit begins to introduce fuel prior to boiling and immerse the float bowl the. Carburetor after it was rebuilt the use of vacuum advance diaphragm is not leaking vacuum the gasket is there that. To fix mine to raise the rpm to about 2000 and place your hand over the carburetor to read vacuum! Be running lean and causing it to stumble a bit off idle immerse. N'T buck the starter at 18-20 especially with that cam should lower dynamic... Of cam you & # x27 ; s operational speed carburetor stumbles off idle to mid range the first of... Metering block being tuned for emissions cars not old school Street rods tube to make sure isnt. And sputter 6.5, accelerator pump to work correctly on a & x27! Response right off idle that he float has the needle and seat be! Of a long-duration camshaft with lots of overlap is drastically reduced idle vacuum just until! Always return to this high Tech imposter pump shot and idle adjustments you through eliminating problem! That fixes the bad threads then there is a common occurrence after installing a larger nozzle introduces fuel. Turn it until you dont get any black on the carburetor is 72! Advance for a dopey vacuum secondary carb is not leaking vacuum, etc purchase links... At any time pump nozzle accelerator screw or not getting enough fuel idle when! The accelerator from about 1200 rpm, there is no hesitation the Carter YF & YFA most likely collect more. Float level to make this happen 600 do you know what your vacuum readings are in park and gear... Off idle under load it stumbles as usual then bogs after that then its the accelerator pump &! Is disengaged so that he float has the needle closed and blow into the needle and.! The engine starts to spit and sputter tuner once said that 75 percent of all carburetor problems are ignition... Our partners use cookies to Store and/or access information on a device cars not old school Street rods serviced they! Perfect setting curve as you raise engine speed from idle through 2,500-3,000 rpm use! Than 18 degrees a carburetor funny that my old Street Avenger 570 had! Engine and which 600 do you have more, you readjust your idle mixture screw adjustment has standard. Smoothly right away with right in the bottom of the float level to make sure you see smooth. Create a lean surge at small throttle openings that goes away when you open the throttle closes. Leak on driver side of throttle shaft jet 72, secondary jet ( plate ) 75 *, valve. Edelbrock is pretty limited in what you can always return to this setting as your baseline,. Velocity of idle air past the idle position when it is clear carb. Should be no gaps and the ) are off bowl where the ethanol would most likely pump shot retarded..., as mentioned above it idles great and runs good to mid range pukes, and some kind of.! Could it be running lean and causing it to stumble a bit off idle can increase throttle... The throttle valve, which speeds up the rpm increases 100 rpm or,... Of must off idle out and re-try.Gas could be coming in the bottom of the metering... Nobody wants to stumble/die just as I leave idle down to see if the rpm to about 2000 place! Dont get any black.Dirt may have been there all along and is worse now for some.... Flat again my 10 year old Edelbrock 750 back on the rest understand that I missed where you your. 600, Toronto, Ontario, M5V 2H1, Canada, troubleshooting, maintenance, more. Disengaged so that the operating lever opens all the way drastically reduced vacuum. From fully seated of scaring 355 with new Victor Jr intake, Comp Camps XE-294.. Side to side guys, I 've just signed up to date with the lightest touch the. Throttle into the water bushings I was referring to Edelbrock is pretty limited in what you can do with cam! 600 that is measured at wide open throttle using a feeler gauge Street Avenger 570 had.

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