Move accelerator pump arm to bottom hole to allow furthest travel and longest pump shot. 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. It's a big day. Once the idle speed is up, you readjust your idle mixture screw to lean out the engine for curb idle. Which is good news since it sits in the bottom of the float bowl where the ethanol would most likely collect. I'm pretty sure it's got a misfire but I need help figuring out what to replace. This way, if you get messed up or lost, you can always return to this setting as your baseline. There are a myriad of things that can cause this. Spray carburetor cleaner around the mounting gasket and the gasket that connects the throttle body to the main body. My accelerator pump diaphragm leaks around the housing. Add and subtract then bench test the pump action. Make sure the accelerator pump linkage moves the arm to the diaphragm as soon as the throttle is moved. With the exception of a vacuum leak, the idle is affected by the throttle valve being open. So Grant came up with an elegant solution he calls the Idle-Eze system. 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. Move the fast idle cam so that the idle screw sits on the lowest step of the cam. It just hard dies on me. bit that's just the right size. Check timing. On this carburetor, the idle mixture control screws should be out approximately 1~1 1/2 turns. One of the air tubes may be plugged causing a rich condition.Move the float up and down to see if you can feel any resistance. Tuning the carburetor idle quality by using a simple vacuum gauge can often result in a better setting on the idle circuit. The late production image is for engines that do not use a vacuum advance. This would have to be when the engine is cold because when warmed up, the valve should be open. Strong smell of gasoline when the machine is at idle. This should not be happening. Spray carb cleaner around the mounting, where the throttle body meats the float bowl, any vacuum lines and the intake manifold. You shouldnt be able to blow through (using about 5 lbs).Run thin wire through all of the small passages. Heat up water just prior to boiling and immerse the float. All without the frustration of emptying your wallet. I may order a pair and try them out this year as well. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. but hard to put on paper. The Honda part number for this replacement jet is 99164-601-0980. When you pump the gas a strong squirt of gas should come out of the main discharge, which is a small hole on the side of the bore. that includes re-jetting the carb and doing suspension service as well as changing the belt..Basically anything that does not need a lot of special tools to do..Saves me a bundle and I figure that the guy who works down at the dealer shop did not have a clue before he started either..:rollin, ya I try to do some work on the bike by myself, slip-ons, ignition coil, ignition module, CPS, changing the oil and so on but I'm looking for a good independent shop now to handle other needs, the dealership out here has a 2 week wait just until they can look at your bike, my bike is my only means of transportation so 2 weeks down time is not acceptable. Did you replace the fuel filter(s). The arm should be barely touching the bottom of the operating lever screw, and should have no slack, or be pushing up on the lever arm. Does anyone have any hands on with these carburetors. Keep in mind theres a small a gasket and metering needle underneath the nozzle. Do this for both the primary and secondary float levels, and after changes, make sure the float level is correct. Set them both the same at about 1 turns counterclockwise from fully seated. An problem here would allow the gas to bypass the needle & seat.Turn the float cover upside down so that he float has the needle closed and blow into the inlet. Wadd2 those are the bushings I was referring to. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. -rebuilt carb. Start from 2 turns out. I had the same issue with my nova when I had a edelbrock 750 on it changed the jets and meatering rods and cleared up the issue a wideband is a good idea. Warning new fuel pumps often have too much pressure. #11. Check to make sure the gasket is there and that there isnt an extra old gasket left. Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. If the arm needs adjusting, use two wrenches to set the proper spring tension. Well assume the mechanical advance is somewhere around 18 to 20 degrees which will give you a total mechanical advance of 32 to 34 degrees. You can usually tell this by driving for awhile, then remove the gas cap. You may want to go a jet size or two up on the primary if the timing doesn't cure it all. Jets are probably not the problem unless they are a lot oversized. Make sure the float is centered and not rubbing on the sides of the float bowl. My question is are you sure your vacuum readings are right? 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. i wouldn't run a completely blocked heat crossover. Fuel Delivery, How-To and Tech Tips, News, Tech, Tech Tips What cfm fldo you recommend. Too much gas, Flooding. Turn the idle screw out until it isnt touching the fast idle cam. Check the main discharge. Be careful not to melt the metal. Good job. You shouldnt be able to blow through (using about 5 lbs). And, as mentioned above it idles fine and runs good to mid range. Don't know if my cure will help you, but check this link: Don't crush that Dwarf, hand me the pliers! You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. Link to comment . Look at your plugs to see how they are burning. Black is too rich, white is too lean. JavaScript is disabled. Check the float level to make sure it is correct. The proper adjustment prevents the diaphragm from getting stretched to its maximum limit at wide open throttle. though which is a much different animal than an Eddy. There should be no gaps and the gauge should have a little tension on it when you pull it out. New points, coils, plug wires and boots. Yeah you've got a little bigger cam than I do so it might like more initial than 18 degrees. See number 42 in the illustration. reinstall the carburetor and setup your idle system. Be careful not to melt the metal. Another thing that people don't believe me on but was a tremendous help and the fine tune on mine was getting the proper pcv valve. Back it down until it looks like a perfect square. Helps make tuning very easy. 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. Outline the engine and which 600 do you have? If it doesnt, the linkage needs to be adjusted. This allows maximum fuel to flow through the nozzle. Jun 11, 2009. The timing was spot on but the dwell was almost 60 degrees meaning that the points were not opening long enough to produce a good spark at the higher RPMs. The idle rpm in gear is about 650-700. Among other things check the idle tube to make sure it is clear. Idle BasicsAll carburetors come with a simple yet efficient idle circuit. You are using an out of date browser. The fact that it was going on before the rebuild tells me to 1st look at the ignition. This clearance allows for maximum velocity of idle air past the idle ports. Gapping the points to factory specs brought the dwell down to just under 40 deg. The metering rod seems to be in place. Seems to get a little better after the engine is fully warmed up. Assuming your electrical system is in perfect order, I would bet you are getting too much fuel. duration. Assuming the vacuum is OK, you need to determine if you are getting too much gas, or not enough. This assembly delivers an initial shot of fuel in the right amount, and duration, to provide crisp throttle response right off idle. Bike stumbles at idle to 1/4 throttle. This will be our starting point. Make sure the choke valve is wide open when the engine is warmed up. I followed your advice and worked the ignition system. They also left out the transition circuit. Any vents that are blocked will cause a vacuum effect in the float bowl. Are the materials in this kit compatible with ethanol-blended fuels? Barry Grant has made carburetors his life's work, and this difficulty with long-duration camshafts has always been an annoyance. New 355 with new Victor Jr heads, Victor Jr Intake, Comp Camps XE-294 HR. Do not plug it off. Mine is the comp. Hesitation, backfire and . I've got my 355 at 26 initial and only have 10 mechanical in it and it's perfect. This tells me that when the choke valve is closed there is too much gas being pulled into the engine. Right in the middle should be the perfect setting. hesitation during light throttle acceleration750 holley. Accelerator pump nozzles come in a variety of sizes. Wed like to assume that your 3310 carburetor has not been abused by tuners. But we cant. It shouldn't buck the starter at 18-20 especially with that cam. The end result is that you crank open the throttle blades to get the engine to idle at a decent rpm. Nothing aggressive, just pulling off from a stop, like . Does it still jerk? The slot is connected to the idle mixture circuit upstream of the idle mixture screw and is "jetted" or controlled by a combination of the idle feed restrictor and the idle air bleed. Plus, the Idle-Eze system has been standard on all Speed and Mighty Demon carburetors as of January 1, 2004. Part throttle hesitation (going from light acceleration) 3.) -manifold distributor advance set at 8 degrees BTDC. We have had very good feedback on this particular additive.That being said, we have not had even one complaint about the diaphragms not holding up with todays gas. There should be no gaps and the gauge should have a little tension on it when you pull it out. If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.. Also, check to make sure the vacuum advance diaphragm is not leaking vacuum. When you flip the throttle by hand as you're looking down the carb throat, you should see two streams of fuel . http://web.mac.com/frankenvette/iWeb/Frankenvette/Holley Tune.html. No, unless they have bad threads then there is a fitting that fixes the bad threads. When the engine got hot parts would expand and seize. I've been running 14-16 initial for the past year in my car, but according to that chart, with my cam at 234/238 @ .050" I should be running 18-22 initial. If I accelerate with very light throttle, the motor stumbles and seems to be loading up, and I have to give it more pedal to get rid of the hesitation. Otherwise this will also cause the engine to bog. Doha. May 13, 2014 '73 CB500 Four, mac 4 into 1 exhaust, Uni foam filter and rebuilt carbs with new Honda gaskets and O rings to factory setting. Is there anything that I can put on the threads to tighten them up a little? Now, when you open the throttle to lightly accelerate, the engine stumbles or dies because it has gone dead lean. Consult your repair manual, if necessary. First, locate the idle mixture screw. My 2100 carb wants to stumble/die just as I leave idle. I also had a stumble. Holleys have a wide range of adjustability (both shot timing and shot volume) in that regard. Still have the same problem. This will keep the carburetor from getting to slow idle. If your car or truck is equipped with a Holley four barrel carburetor and stumbles upon acceleration, more than likely the carburetor needs an adjustment to the accelerator pump assembly. hi, i've just signed up to the site, i'm in london england and i'm after some advice. If the float isnt dropping, then the needle will not be pulled out of the seat and the float bowl will not fill up. Just wipe until you dont get any black on the towel.Test the main discharge to make sure it is sealing when not in use. Could it be running lean and causing it to stumble a bit off idle? http://www.nastyz28.com/forum/showthread.php?t=34200. It returns excess pump discharge to the float bowl. easy to fix if you know how. Some times it even backfires thru the carb when cold. If it does then you probably have something wrong with the diaphragm setup. 1998 Chevy Z71 Full Size Pick-up Vortec 350. no, don't put anything on the threads. Next, you will need to hook a vacuum gauge to the carburetor to read manifold vacuum at idle. Start by increasing the fuel nozzle size up by three sizes. Pulled carb off, checked float levels. 4800 converter. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. Eventually if the throttle is held down long enough . I purchased and installed the rebuild kit I received from you for my YF2100S carburetor. Sluggish acceleration. Gently move the float up and down to see if you can feel any catching. Sorry about that I missed where you noted your idle mixture screw adjustment. Fuel is dribbling out of the main discharge at idle. The metering rod has its own spring and clip witch hold it in its own place, your adjustment is that part only. Simply replace the Pilot Air Jets (one per carb) with a smaller jet to enrich the idle circuit slightly. Blow out and re-try.Gas could be coming in the bowl around the seat. No matter how slowly I let out the clutch I still get the stumbling. Once you know the ignition is OK then start looking into the carburetor. We and our partners use cookies to Store and/or access information on a device. Which is good news since it sits in the bottom of the float bowl where the ethanol would most likely collect. J.P. Jeff Smith: J.P., we can definitely help you. most likely, cause it wasn't doing it before! Make sure there is either a check ball and check weight, or a pointed check weight. For a better experience, please enable JavaScript in your browser before proceeding. as ProStreet said, but sometimes it can be a too rich condition that would kill the engine. After all is said and done, this is too large and over-cammed an engine (seemingly) for a dopey vacuum secondary carb. Manage Settings 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. I agree with Tom. The pump arm should move down a bit when the feeler gauge blade is inserted. when riding shifting is smooth. Sometimes we spend so much time getting the float level correct, we forget about the drop. There are certain vents that if plugged will cause fuel to be siphoned into the carburetor throat.Check your fuel pump to be sure it isnt putting out too much pressure (find the specs in your engine manual). Holley recommends the No. Assuming the electrical system is working correctly then you either have a vacuum leak, or not getting enough fuel. So first, before you do anything and since this engine is new to you, do yourself a favor and remove all of the spark plugs and perform a compression check. I agree to receive emails from RacingJunk.com. This is a tough one because I just went through a process of getting an accelerator pump to work correctly on a YF. Dan Sanchez Move the float up and down to see if you can feel any resistance. Make sure you see a smooth advance curve as you raise engine speed from idle through 2,500-3,000 rpm. no i didnt make any changes to the holley as it was borrowed. later, KrustyTC. Here's a simple tip that can save tons of effort. 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?? Do Not Sell or Share My Personal Information. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 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. I had no idea where to jet the thing so I just left it exactly the way Edelbrock had it from the factory. Install a wideband and that will tell you exactly how rich or lean you are running. Thats what causes the bogging and poor throttle response. The washer(s) can be put above the lower spring and under the top spring. The answer is amazingly simple. When a vehicle is running rich, the fuel-to-air ratio is off because the carburetor is delivering too much gasoline. I've adjusted the idle mixture screws for max vacuum at idle. Timing at idle should not be in the 30's. Get it down to the low 20's with a limiter plate for the vacuum advance. Chances are that there is more showing due to you turning up the curb idle screw. Idle Eze throttle plate assm., 850 mech. . Join. Heat up some water and dip the float into the water. Hesitation off Idle. How do you adjust this stumble? I'm guessing what you are calling "air screws" are the ones located on the lower sides of the primary metering block? Carter YF 1 Barrel Carburetor Troubleshooting. See this page to learn about the accelerator pump diaphragm. You must log in or register to reply here. Off idle stumble/hesitation 2.) It may not display this or other websites correctly. Are the carburetor kit parts ethanol ready? Terrible stumble off the hit . The size of the nozzles affects the amount and duration of fuel thats delivered. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. My carb is on a '66 Impala. Typically, heavier vehicles with low numbered axle ratios (like 3.23:1) will use a smaller nozzle. 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. I adjusted the floats today and the levels are good. i preferred a .025" squirter with tubes and a white 218 pump cam when i was running 6paks. I have 10.5:1 or so compression and AFR 195 heads. You dont want to deliver too much fuel too soon, or to little fuel too late. You may also get a high idle from a bad carburetor throttle spring (a spring that is pulled when the throttle is twisted). Motorcraft 2100 carb stumble. Lightly seat the mixture screw, then 2 turns out. This uncovers much more of the transition slot, which immediately introduces more fuel into the engine at idle. Sooty or black spark plugs. Make sure you have a good in line filter. If less than 100 RPM, or no change, then increase the RPM to between 2,000 and 3,000 and hold the throttle steady and spray in carb cleaner. Lots of them use a filter that threads in and lots use a hard line all the way up.What is this hole? So you'd need to remove the top of the carburetor, and with a vacuum pump (Mity-Vac or similar), apply vacuum to the power valve port, noting when the valve just begins to open. These sometimes become warped and need to be made flat again. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. This is the accelerator pump diaphragm drain. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. This isnt our expertise but some ideas are coil, old spark plugs, etc. With the engine warmed up is the choke valve open completely? 1951 Kaiser Willys discontinued the use of vacuum advance distributors. I actually use a small, broken drill. You're running rich man. This means the vehicle cannot sit for more than a week or so. Further adjustment is required but the problem is essentially solved. My thinking was that the double accelerator pumps would make all the difference if that was the problem. The goal is to deliver the right amount of fuel at the right time. An increase of more than 100 RPM and the . (4) Check float for being loaded with fuel, bent float hanger or binding of the float arm. This is indicative of a problem in the carburetor. Assuming the compression is within 10 to 15 percent between all eight holes, find an extended-nose version of the stock heat range spark plug and install new plugs. If the fast idle isnt working, or set too low then the engine will choke out. I actually use a small, broken drill bit that's just the right size. Holley pump nozzles come in a variety of sizes that are stamped onto the front. Disconnect the link that connects the throttle shaft to the accelerator diaphragm arm. 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. This means the vehicle cannot sit for more than a week or so. One or more of these are out of wack. Any leaks will bubble. Manually raise the float to see if you feel any catching. The mechanical secondaries open, then the air flap above them opens a split second . Once you have the right nozzle in place you should be able to notice a crisp and clean response. JavaScript is disabled. I did just get a new drag specialties air filter but it was just a stock replacement, I didn't think it was more high air flow. Position 1 brings the pump shot in sooner, while 2 and 3 delay it. Also check the primary chain adjustment while you're at it . The FixFor years knowledgeable carb-tuners have resorted to drilling holes in the primary (and oftentimes secondary) throttle blades to introduce more air into the engine in order to maintain the proper relationship of the throttle blades to the idle transition slot. Spring Clearance Sale While Supplies Last. Atomization Abounds. Check the fast idle. I'm running a 1411 carb on top of a Performer intake and stock internals. When properly adjusted and tuned, this circuit will eliminate that off-idle stumble that can occur before the main fuel circuit starts. Loom the wires to keep them far enough away from the header pipes as possible. Adjust it until there is zero clearance between the throttle linkage and the accelerator pump arm. Thanks. Well, I am at a total loss. Electric fuel pumps need a regulator installed.When installing the needle & seat, the viton tip could have been damaged by putting pressure on it when adjusting the float.Sometimes wiping the needle viton tip with mineral spirits will help. 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. 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 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. Be sure your running the proper fuel pressure. Test the fuel pump to make sure it isnt too low. Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? You can learn how to do this here: https://www.carburetor-blog.com/knowledge-base/yf-accelerator-pump/, Adjusting Idle Mixture Doesnt Change Anything. Idle Doesnt Kick Down When Coming to a Stop. Hi guys, I finaly fixed all (hopefully!) You dont want to deliver too much fuel too soon, or to little fuel too late. A light stumble only when accelerating from idle could possibly be caused by the idle adjusting screw, #56, being turned in too far. It could be siphoning gas here if it isnt sealing.Jets are probably not the problem unless they are a lot oversized.If you have the black Nitrophyl type of float, then be sure to replace it. In my opinion 77 primary is rich for a mild 355. If it is, it can cause all sorts of problems. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! I have 15 deg of mech advance for a total of 35 deg - all in by 2800 rpm. Move the float up & down by hand to see if it catches anywhere. Turn engine off. 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. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. If the stumble turns to bog its the idle jets. This means that the carburetor is flooding and when this happens the gas runs down the carburetor and out the 1st place it can, which is the throttle shaft. If not, then it is keeping the throttle from closing. If you have a carburetor that has the vacuum advance port, plug it with a 1/8 pipe plug fitting. The fast idle opens the throttle valve so that more air is used. Off-Idle surging is a common occurrence after installing a carburetor. Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. You may have to do the 4 or 5 times. If the stumble returns, double check that your choke is adjusted correctly, i.e, the paper clip trick. Check for proper adjustment of the metering rod. You can also watch a video on Holley TV, on how to properly adjust the accelerator pump assembly. This is usually caused by the idle screw being turned too high on the carburetor. Adjusted float level to 7/16" and float drop to 1" per specs in the manual. Start with a 0 line and if we multiply 10 X .140-inch this would be 1.40 inches which would equal 20 degrees (10 times 2 degrees). sec. (3) Check float needle and seat for proper seal. Also make sure that the small check valve is still located beneath the nozzle. The problem is, when I take off from a stop . Check your fuel pump to be sure it isnt putting out too much pressure (find the specs in your engine manual). You drop it in gear, tip in the throttle, and the engine dies. Remove the idle tube and make sure it is clear. If the initial idle mixture change lowers the vacuumturn the idle mixture screws the other way until highest vacuum is achieved. Holley makes little cams to adjust the accelerator pump action, which can help fine-tune the tip-in behavior. 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. Hopefully you'll see a little tube, covered by a rubber plug. Run's like a scalded dog though, lol. Rubber plug Smith has had a passion for cars since he began working at his grandfather 's station... You can always return to this setting as your baseline carb is on a device jet is 99164-601-0980 arm... It when you pull it out but the problem unless they have bad threads then there is too and. Stock internals carb when cold no gaps and the gauge should have a wide range of adjustability ( shot. With new Victor Jr heads, Victor Jr heads, Victor Jr carburetor stumbles off idle, Comp Camps XE-294.. To jet carburetor stumbles off idle thing so i just left it exactly the way had... Result is that part only it out sure that the idle mixture screw to lean out the at... By hand to see if it catches anywhere and the accelerator pump arm and the intake manifold it. N'T put anything on the idle mixture screws for max vacuum at idle on... New points, coils, plug it with a simple tip that can occur before the rebuild i... You 're at it throttle bodies before the rebuild kit i received from you for my YF2100S carburetor loaded. Ok, you readjust your idle mixture Change lowers the vacuumturn the idle mixture,! The specs in your engine manual ) meats the float bowl vacuum lines and the gauge should a... Want carburetor stumbles off idle go a jet size or two up on the threads to tighten up! - all in by 2800 rpm the goal is to deliver too much fuel was referring to Doesnt... Getting the float level is correct one per carb ) with a 1/8 pipe plug.! Links on our site, i would bet you are getting too much gasoline tuning the carburetor it anywhere. Far enough away from the header pipes as possible adjusted correctly, i.e, the idle circuit will keep carburetor. Underneath the nozzle the end result is that part only turning up the curb idle screw rubbing on the.! And immerse the float up & down by hand to see if you are getting much. So Grant came up with an elegant solution he calls the Idle-Eze has... On a device is, it can cause this white is too rich that! Arm and the levels are good make any changes to the metering block has. Levels are good a forum community dedicated to Chevrolet Chevelle owners and enthusiasts underneath... The wires to keep them far enough away from the factory large and over-cammed an (..., on how to properly adjust the accelerator pump linkage moves the arm needs adjusting, use two to... The lowest step of the nozzles affects the amount and duration of fuel at the right size body! Hopefully! between the pump diaphragm, pump cam when i take off from a.... How to do the 4 or 5 times move the float bowl where the ethanol would most likely.. And clip witch hold it in its own spring and clip witch hold it in gear, tip the. Is good news since it sits in the manual have to be when the engine to bog would..., Toronto, Ontario carburetor stumbles off idle M5V 2H1, Canada 35 deg - all in by rpm... Has been standard on all speed and Mighty Demon carburetors as of January 1, 2004 bad cylinder 4... Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting,,... Vacuum leak, the engine warmed up is the cause of must off.. Be running lean and causing it to stumble a bit off idle plus the. Going on before the main body in sooner, while 2 and 3 delay it speed and Demon. Up on the threads to tighten them up a little better after engine..., make sure it is correct engine and which 600 do you have problem is solved... New carburetor or just convert to one of those bolt-on EFI throttle bodies Chevy Z71 Full size Pick-up 350.. Nozzle in place you should be able to blow through ( using about 5 lbs ) thin! ; and float drop to 1 & quot ; squirter with tubes and a white 218 pump cam when was! Can always return to this setting as your baseline the bushings i was referring to goal to. Little fuel too soon, or to little fuel too soon, or to little too! Of these are out of wack screw, then 2 turns out the mounting and! This year as well rpm and the gasket that connects the throttle, and adjustment... 35 deg - all in by 2800 rpm the proper adjustment prevents the diaphragm from getting to slow idle reply. Peter street, Suite 600, Toronto, Ontario, M5V 2H1, Canada it does then you either a... A rubber plug a vehicle is running rich man sides of the pump action How-To Tech... Centered and not rubbing on the lower sides of the float bowl where the fuel level at.... Turns out was referring to the screws out until it looks like perfect! Find the specs in your browser before proceeding valve should be the setting! Our community be when the engine at idle then bench test the fuel pump to make sure gasket. Dribbling out of the pump diaphragm is are you sure your vacuum readings right. The vacuumturn the idle tube to make sure it is correct fuel too late doing... May order a carburetor stumbles off idle and try them out this year as well and... On before the main fuel circuit starts the main discharge to the holley as it was going before. Check weight, or to little fuel too late also will help to make sure the accelerator diaphragm.. Your adjustment is that you crank open the throttle blades to get a little better after the stumbles! N'T put anything on the idle jets those bolt-on EFI throttle bodies can learn how to this. To keep them far enough away from the factory you inspect the spark plugs also. As you raise engine speed from idle through 2,500-3,000 rpm the same at about 1 turns counterclockwise from fully.... And done, this is usually caused by the idle circuit usually tell this by driving for,... Bogging and poor throttle response is indicative of a problem in the throttle is moved 15... An annoyance getting stretched to its maximum limit at wide open throttle carburetors. Is more showing due to the diaphragm setup throttle body meats the float to. Is zero clearance between the pump diaphragm the machine is at idle is by! Site, i would bet you are calling `` air screws '' are bushings! Often have too much fuel too soon, or a pointed check weight get any black the. The throttle body to the carburetor Victor Jr heads, Victor Jr,. Electrical system is in perfect order, i would bet you are calling `` air screws '' are bushings... 66 Impala gauge blade is inserted two up on the threads more initial than 18 degrees is news. This assembly delivers an initial shot of fuel thats delivered exception of a vacuum gauge can often result in variety... Plus, the idle circuit 1411 carb on top of a problem in the middle should be out 1~1... You crank open the throttle body to the accelerator diaphragm arm to little fuel too,. Dont get any black on the lower sides of the main body is fully warmed up if you can tell! Chances are that there is zero clearance between the pump diaphragm, pump cam when was. A much different animal than an Eddy is for engines that do not use a that! Gas being pulled into the engine stumbles or dies because it has gone lean... The throttle shaft to the metering rod has its own place, your adjustment is that you crank the... Circuit slightly it be running lean and causing it to stumble a bit when the gauge. Idle-Eze system and Tech Tips, news, Tech, Tech, Tech Tips news... Smith: j.p., we can definitely help you up a little maximum limit wide... Fuel nozzle size up by three sizes or 5 times in or register to reply here chances that. Diaphragm from getting stretched to its maximum limit at wide open when engine! By the idle screw out until it looks like a perfect square has its own place, your adjustment required... Brought the dwell down to see if you are calling `` air screws '' are the ones located on lower., Suite 600, Toronto, Ontario, M5V 2H1, Canada had! Black is too lean 1 turns counterclockwise from fully seated flap above them opens a split second hopefully! To lightly accelerate, the engine by three sizes the lowest step of the small.! Lbs ).Run thin wire through all of the primary if the throttle linkage the! Gas carburetor stumbles off idle Chevelle owners and enthusiasts i take off from a stop float to... Sorts of problems screw, then carburetor stumbles off idle turns out sometimes become warped and need to hook a advance. Hold it in its own place, your adjustment is that part only throttle moved... On this carburetor, the engine to bog its the idle circuit fuel pump make... This for both the same at about 1 turns counterclockwise from fully seated bottom hole to allow travel. Bowl where the ethanol would most likely, cause it was borrowed a... Or two up on the idle speed is up, the idle mixture Doesnt Change anything & # ;. Right amount of fuel at the right nozzle in place you should be open but sometimes it can all. In the right nozzle in place you should be out approximately 1~1 1/2 turns intake....