This tunnel ram is set up with a pair of 0 . Its pretty specific in the manual to run no more than 6 psi, more like 5 or 5.5 psi. If, for example, you found the accelerator pump squirter was too large and installing the correct 31-size squirter reduced the hesitation, then that points you to try even a smaller squirter like a 28 or even a 25. Have been thru the normal diagnostics - timing is 24 degrees . You can pick up a rebuild kit pretty cheap at your local auto parts store. Some AFB's, or Weber Marine use a check ball and a spring. And that is measured at wide open throttle using a feeler gauge. Thanks for you're input. Edelbrock idles well but backfires ( seems like it's in the exhaust manifolds ). Make sure you have the accelerator pump shot at the max discharge position. This article leaves out a bunch of detail. Executing all these suggestions will be a time-consuming process and not all may contribute to improving drivability. I adjusted the linkage to the accelerator pump (as Edelbrock site recommended) and it seemed to improve the hesitation / bog, but it still is there. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. 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. I too had bog problems with my 1406. It only happens when it's warm. Terms of Service. And if so will one of the cheap spectre or auto parts store regulators will work alright? Wed like to assume that your 3310 carburetor has not been abused by tuners. But we cant. If it is, it can cause all sorts of problems. On my 82 F150 truck I have always had this issue and I have been trying to resolve it since the motor was rebuilt and I cant get it resolved. Now for where I have stuff set at: fuel: 6psi. I think a 600 to 650 carb will yield better off the line and cruise performance. The linkage should move and squirt a small amount of fuel with the lightest touch of the linkage. The carburetor is a Holley 750 with vacuum secondary. I understand that I can unsubscribe at any time. If any of the components in your fuel system stop working correctly, like your fuel injectors, fuel pump, or fuel pressure regulator, then your engine won't get the proper amount of fuel it needs for combustion. One thing to check is that the advance weight in the distributor has the springs attached.. One other possibility is the idle discharge. You dont need to drill throttle plates. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. I have a 1978 302 in a 1926 model T. I recently installed a edelbrock performer cam, and had the heads rebuilt. The "Bog" simply means the engine is not receiving enough fuel when you go to wide open throttle. Fuel octane rating makes no difference. You can check this by hooking up a timing light and watch the timing mark move when increasing engine RPM. If your secondaries are opening . No money in the budget for long tubes just yet, I had the shorties so I used them. Otherwise this will also cause the engine to bog. The problem is hesitation on acceleration fron stop after the engine is warmed up. This will make the leather too spongy and will probably fail. For a better experience, please enable JavaScript in your browser before proceeding. If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. Put a double pumper carb up there, maybe an 850 (like a chokeless HP) and watch that flat spot disappear. Privacy Policy. But occasional run on, I can deal with. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. Edelbrock Carburetor . Terms of Service. Job one with any Edlebrock carb in the experience of many board members here is to move the accelerator pump linkage to the hole closest to the fulcrum (maximum pump shot) and to check the float height per Edelbrock instruction. Since 2003, Jeff has held various positions at Car Craft (including editor), has written books on small block Chevy performance, and even cultivated an impressive collection of 1965 and 1966 Chevelles. Loom the wires to keep them far enough away from the header pipes as possible. To bring the curb idle back to the ideal spot of uncovering about 0.030 of the transition slot involves drilling air bypass holes in the throttle blades. What should it be?^^. No fuel coming out means you have a restriction between the pump well and the main discharge. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. 04-20-2010, 09:42 AM. Another thing, get a vacuum guage to tune your mixture screws with. Still have the same problem. you overlooked the holley! I don't seem too have any issues except the very occasional bog if leaving from a stop very very slow. Fuel Delivery, How-To and Tech Tips, News, Tech, Tech Tips 3) Faulty Fuel System. Apply a couple drops of oil to the pump. The AVS name is an acronym that stands for Air Valve Secondary. I like the sound of bumping the timing. Krawk101 8 mo. Any part-throttle stab is smooth. Motor pulls clean to 6K, haven't tried taking it higher. There are three main components of the accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Power valve is probably opening because that rough idle camshaft is only allowing the motor to make 4 or 5 inches of vacuum.if thats the case try a 3.5 valve if your gauge is showing 4, 4.5 if 5 on the gauge etc..theres a small Allan set screw in the bottom of the base plate to allow you to open the secondaries at idle (slightly!) The only thing you can do is soak the carburetor in a cleaner (we use simple green), then try blowing it out. As you move the pump up, the well will fill up using the slot described earlier. If you find it necessary to replace the 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. age of adaline comet. No dice. I have a completely rebuilt Edelbrock 600 sitting on a 1" spacer on an Edelbrock intake on a mild build 350 SBC with manual fuel delivery system. The Edelbrock tuning grid is formed into four quadrants, or squares. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Turn that distributer counterclockwise a bit and then drive it. I used the .043 nozzle. 1406 sounds a little small for your mods. You dont want to deliver too much fuel too soon, or to little fuel too late. I followed Pony Carbs timing instruction to the letter and the problem continues. Push the pump down and watch it squirt gas out of the main discharge. 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. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. The arm can be adjusted by tightening or loosening the screw and spring assembly. Carb is a 1411 with 110 primary and 107 secondary jets, metering rods are 75x47,float level is adjusted, fuel pressure is 5.5 and timing is 36 @ 3000. What is the AFR Correction at idle and at cruise? Have fun! . And i put a 1470 accelerator pump in . Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. I was wondering about this hesitation issue I've been having. I am also running the edelbrock air/fuel gauge and also running an aluminum intake. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. Your email address will not be published. Great info, I too had to change my springs and accelerator pump shot. The Carburetor Shop LLC. elcamino65Memberfrom washington. . If they are way off, thats good. It's set up the way it cam out of the box other then the idle and idle mixture settings. Edelbrock 1470 - Carburetor Accelerator Pump Assembly (5) $18.95. If the initial idle mixture change lowers the vacuumturn the idle mixture screws the other way until highest vacuum is achieved. Well, I am still running a carb plate and phenolic .5" spacer. A new leather cup type of accelerator pump will need to eventually expand. Typically, heavier vehicles with low numbered axle ratios (like 3.23:1) will use a smaller nozzle. Edelbrock carb stumble,hesitation,bog. by coop Tue Dec 29, 2009 8:05 pm. Start by increasing the fuel nozzle size up by three sizes. Eldon, Missouri 65026 . This test is best done with the carburetor off of the car. I've had this truck in Check out 8 reviews on Holley 0 90670 4 Barrel Secondary Carburetor: "Bought this carb for my Bronco 79 (351M) which I use off road. A forum community dedicated to hot rod owners and enthusiasts. Following up on my other replies in this thread, I took the car out for the first time since I removed, disassembled and cleaned the 1406. As the throttle opens, this hole is exposed allowing more air fuel mixture to enter the intake. You will find this passage just above the idle mixture hole inside the bore. I adjusted the low and high as directed by turning set screw until engine lugged down then turned one complete turn counter clockwise. If you loosen the screws on the front of the carb at the base plate 1/4 turn and it doesn't change idle speed, go back in and go 1/4 turn tighter than when you started to see if it drops idle. Good deal! Eventually the deterioration will reach the point that the vacuum advance no longer adjusts the timing, causing the vehicle to hesitate when the engine attempts to move the vehicle's weight. If it still bogs, you probably need a bigger squirter. The hole closest to the pivot point on the plunger lever is that setting. At normal cruising no backfiring. You can also watch a video on Holley TV, on how to properly adjust the accelerator pump assembly. Not that I could tell when I had it apart but I did notice the weights were numbered differently (41 and 42 IIRC), don't know if that means anything or not. When you flip the throttle by hand as you're looking down the carb throat, you should see two streams of fuel squirting across the venturi. Thats what causes the bogging and poor throttle response. It just takes a lot longer to really dial in a carburetor compared to fuel injection where you just hit a few keystrokesbut the effort is worth it. A leaky check ball passage can cause gas to get siphoned while idling, or just after turning off the engine. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! I just changed the step-up springs to the silver (8" HG) ones and it had a HUGE improvement. We just need to run you through eliminating the problem area. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. Terrible stumble off the hit . How to test the accelerator pump while on the bench. If you don't know what an accelerator pump is, it's a squirt gun for fuel. When I first start the engine it runs great, and idels in great. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Adjust the accelerator pump rod so it is longer(bend it) just enough so it fits in the hole just right while the carb is closed. For rubber cup pumps, apply a dab of lithium grease to the cup. Jump to Latest Follow 1 - 20 of 40 Posts. 10 positive effects of population growth on economic development My 1406 carb hesitates (a little) if I stab it to the floor below ~3500 rpm. ago. This opens the throttle blades to uncover what is called the transition slot. It also prevents the distributor advance from operating, causing a late timing issue. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Most carburetors use a piston or diaphragm-type pump. The pump arm should move down a bit when the feeler gauge blade is inserted. Learn how your comment data is processed. Backfires occur in engines with severe malfunctions, such as those with diverter valve issues, exhaust leaks and faulty catalytic converters. Edelbrock 600 CFM carb, #1405. Acompanhe-nos: bonsall oaks development Facebook. and close the primaries back to where they need to be.make sure the timing is right along with all the basic carb settings before checking the vacuum.it will probably drive ya nuts til you get it calmed down but keep trying. In addition to this lack of power, a vacuum leak can also cause the engine to idle roughly or even stall. Makes a poping or pinging sound not a real loud backfire. The fuel pump will be drawing air instead of fuel, leaning out the mixture. 1967 - 1972 F-100 & Larger F-Series Trucks - F100 hesitation stumble when accelerating from stop - i have a 1969 f100 2wd auto 3 speed i think 360 v8 autolite 2100 carb with 1.23 stamped on it main question is -it stumbles when stepping on pedal now from stop before i tried re-adjusting the carb it would spin the. Then, check the clearance between the accelerator pump diaphragm arm and the operating lever screw and spring assembly. Report back. I believe this was from the previous owner trying to get the truck passed for emissions testing. Carb: factory rods and jets, springs. For more information, visit www.holley.com. The formula says that my 307ci motor at 104% VE at 6000 rpms needs a 554 cfm carb. You must check this with the vacuum advance disconnected. This is very important and typically where we see Holley carbs set incorrectly. Prior to that had the Carter which i simply couldn't get tuned properly. Also the floats in the carb were moving freely. Let us know what happens. After each nozzle change, turn the engine on and quickly open the throttle to see how the carburetor reacts. As far as carb size goes, there is a formula that will get close. Suggestions will be drawing air instead of fuel with the lightest touch of the accelerator pump.! Avs name is an acronym that stands for air Valve secondary edelbrock Victor, Jr. intake and... 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