Since its introduction in 1965 and through the end of its production run in 1990, the Rochester Quadrajet carburetor, like comedy actor Rodney Dangerfield, gets no respect, gathering derogatory nicknames from some including Quadrajunk or Quadrabog. Blocks, Marine If you dont want it give it to me. Ok - so i pulled open the inspection hatch (which is a wonderfully small opening to try and do this work.) While there are other issues that may cause similar reactions within the carburetor, often the problem can be traced back to the accelerator pump system. When adjusting engine idle, it is important that the primary throttle blades remain in line with the throttle body transfer slots, or performance, fuel economy, and driveability will suffer. Hitches, & The idle is set at 900rpm without vaccume advance plugged in. Possibly sucking air someplace? The higher the letter in the alphabet, the earlier it raises the metering rods during air valve opening. It's a QuadraJet. Video, GPS Chartplotters & As the fuel enters the carburetor, it must pass through the inlet valve, often referred to as the needle and seat assembly. Fuel pick up in the tank? 01. They were touching the bottom of the air cleaner, and apparently they were only arcing under acceleration under load. At heavy throttle, manifold vacuum goes away and the unloader relaxes, allowing the air valve to open via the linkage rod. Ford did it via the 4300/4300D/4350 carburetors. your boats Gel Coat Match, Shop If I have it in 3rd gear, 40 mph and hold it WOT it will pull strong to approx 3,000-3,500 before it bogs. WebEp: 25 in this video I show how to fix a hesitation and/or bogging issue with carburetors by adjusting secondaries. When you study the Quadrajet's architecture it's apparent it has nothing in common with Holley-based carburetor designs. Rails, Marine Tools & Tool Pumps, Livewell Aerator Pumps But, if you try to jump on it, let's say more than 1/2 throttle all at once, the car sounds like it is backfiring or popping in the carb. The throttle position sensor provides throttle position feedback to the ECM. All, Anchor & If you accelerate it goes away and pulls smooth. The rod connects to the choke unloader which serves as: 1. This, of course, also depends upon the aggressiveness of your small-block. Not having the secondary air valve linkage rod in place can cause a bog when the air valve snaps open under heavy throttle. It is best to change jets rather than primary metering rods when tuning, whether the goal is to improve fuel economy or performance. Outboards, Shop You can modify the choke unloader to speed up the opening rate to 1 to 1 1/2 seconds. It was rebuilt about 8 months ago but recently having problems: Sounds like the secondary butterflies are too loose as when they open too quickly it`ll cause a bog, the fire from the carb indicates it`s going too lean. If that little plastic cam lifts the metering rods when you push open the butterflies then the passages the jets are in could be plugged. Insurance, Boat Kind of an enrichment/acceleration feed to get the fuel sucking through the secondary bores. When a Quadrajet is installed in a stock application it's operating in the environment it was designed for. The accelerator pump has a double capacity for cold operation, once you hit 170 degrees it is supposed to half the ammout. I'll take a look when I get home and report back if that fixed it. Well said Tech. Authentication and pre-purchase inspection service still available. Parts, Rule 1500 GPH Automatic The air valve may be adjusted by first backing off the Allen head lock screw (located on right side of the air horn) and then turning the adjusting screw clockwise to tighten the tension, or counterclockwise to loosen using a small screwdriver. I'm having a problem with bogging when the engine is cold. High Back Reclining Helm Seat, Cabin and I realized that some of the pieces to connect the choke are gone. WebHow to de-bog your Quadrajet part 1 Tyler's Forgotten Car Rescue 34.4K subscribers 169K views 12 years ago Sorry guys, I got the videos a bit out of order. The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. "Detroit hasn't felt any real pride since George Bush went to Japan and vomited on their auto executives, I tell you whut". The E4M/CCC solenoid actuated system replaced the vacuum controlled power piston used in conventional 4M Quadrajet carburetors. Harware, Marine Nuts, Bolts, & 1,364. I know almost nothing about qjets, but I'm trying to learn. Is it a good stream like you'd piss after drinking 3 PBR's? Tops, Bimini Top For a better experience, please enable JavaScript in your browser before proceeding. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. Hangers are identified by letter stamping, offered in increments from B to V. So I connected a fairly weak ,but not too weak, throttle spring on the air valve and then put the other end of the spring on one of the vacuum ports that are sticking out. I don't know if its a problem but Boats, Propeller Parts & The Quadrajet has mechanical secondaries, which open promptly when you mash the gas. Accessories, Pontoon Bimini Be sure your float level and fuel pressure is correct.If you have allready rebuilt it ,that may be the trouble. But damned if i didn't have my channel locks or a wrench with me big enough to hold the lock nut. When the motor is warm it hesitates but barely. Not sure what it took to make it run this well, but I am pleased. It ain't worth the 7 dollars for all the grief you can suffer. Parts, Sacrificial Anodes & Holland Tunnel-sized secondaries deliver brute power if properly timed. Smoke For a better experience, please enable JavaScript in your browser before proceeding. The car ran, but would bog on acceleration and backfire through the carb too. You must log in or register to reply here. Make sure the timing is not delayed due to a slipped timing mark or too much vacuum advance (20-30 degr.). Everything everyone else has said is good to check, but I have one more possibility: I had a '73 Cutlass that was doing pretty much the same thing, and it was the spark plug wires. Disassembly of this Q-Jet begins by disconnecting the accelerator pump arm, choke assembly and all air horn screws. Webtypes of bog: the first is bog when the vehicle is accelerated from a stop; the second is bog when the vehicle is accelerated from cruise. Racks, Fish Finders, Sounders JavaScript is disabled. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. This added to my concern for the pick up tube. The rod connects to the choke unloader which serves as: 1. Because GM's Rochester Carburetor Division produced so many Quadrajets in 25 years there's still a generous inventory of cores out there to choose from. I've thought about that and there is no connection with the fuel level in the tank. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! no vac, engine off, that's right. Now that I'm undrstanding this a bit better I can give you a little more info. http://s1232.photobucket.com/albums/ff362/Nickvt/, http://s1232.photobucket.com/albums/ff362/Nickvt/1934 Plymouth/, http://www.youtube.com/watch?v=Yn420s-LDzY, http://s80.photobucket.com/albums/jvideos/?action=view¤t=2011_09110020.mp4. We will see what happens. One nice thing about the Quadrajet is fuel economy if you keep your foot out of it. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Meters, Marine Electrical Panels I was just out playing with the carb on the '70. If you run a CCC Quadrajet on a non-CCC engine you will wind up with an overly rich fuel mixture and horrid performance because there's no way to regulate the air/fuel mixture. I checked the lock bar out and it is working fine. Protection, Dock Storage & Terminal Yours should be around 2 seconds. GPS Chartplotter and Fish Finder Combo, Find While a traditional, square-bore 4150 or 4500 series Holley 4BBL may offer the absolute maximum performance required for all-out drag or circle track racing, a properly prepared Quadrajet, or Q-Jet, can certainly give them a run for the money. Big-blocks want 800 cfm. Hardware, Boat Trailer Webtypes of bog: the first is bog when the vehicle is accelerated from a stop; the second is bog when the vehicle is accelerated from cruise. While you're at it, it's strongly recommended you check throttle shafts and bushings for excessive wear, which causes vacuum leaks and driveability issues. Trailer Winches, Shop Another possibility, and it is real. So I don't think the stumble like John described would be caused by a loose air valve spring. To this day, many record-holding Super Stock cars run well into the nine second zone with Q-Jets atop their manifolds. Fenders, Boat Trailer http://www.73-87.com/7387garage/drivetrain/myqjet.htm. Detectors, Binoculars & Thanks folks!!! Rafts, Paddle For a better experience, please enable JavaScript in your browser before proceeding. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. Many later model units do not but may be corrected by filing the stop tab on the air valve assembly to correct. Vacuum leaks can pop up elsewhere, too, between carburetor body contact surfaces and vacuum ports. (You must log in or sign up to reply here. Could you explain a little more what I am looking for? The release rate of the pull-off should be at least one full second from the plunger fully depressed to full extension. Systems, Marine Plumbing I would guess that with less restriction to the flow of fuel the carb could need some tweaking? "Quadrabog," "Quadrajunk," and a host of other time proven nicknames define GM's most notorious four-barrel carburetor. The primaries must open considerably to reach the "tip in" point. Axles, Boat Trailer Tie Maintenance, Boat Cleaners & However, when you start making modifications such a hot roller camshaft, aftermarket induction and heads, and a host of other performance elements the Quadrajet struggles to keep up. That was in park as it's an automatic(th350.). Sounds like a possible float issue to me. Considering the carb is a recent rebuild i wasn't really surprised. This is known as electronic mixture control. Accessories, Marine DC Power Plugs Bog from a stop is virtually always (and generally erroneously) diagnosed as a faulty accelerator pump (see the section on accelerator pumps for testing). pump ck. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. I am no expert on the Q-jet, so I'd like some thoughts on adjustment. I have a quadrajet on the 454 in my truck, electric choke etc. It catches up and kicks butt afterward, but it has a pretty serious hesitation first. They are actually about as simple as a stone axe. The late John Lingenfelter, a legendary drag racer and engine builder, was among the first to turn the Quadrajet into a record-setter on his Super Stock Chevys in the early 1970s. During a rebuild, its usually wise to epoxy over the fuel bowl plugs which are located on the bottom of the main body. They are actually about as simple as a stone axe. :thumbsup: Sure it would.if I wanted to hold the air valve open all the way all the time. & Rings, Prop Nut Kits & Accelerates smoothly and with no problem. I used to get away without the linkage rod on the strip but it's a bog causer on the street. Engine is 1986 model mercruiser MIE 340 big block with quadrajet carb. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. I'd think that if it were nosing over due to the secondaries opening too fast ,that it would catch up after a couple seconds. Instruments, VHF Radios & Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! Here is a scenario that may help. Cable, Marine Batteries & They are actually about as simple as a stone axe. That is, until my last outing Under heavy acceleration, the engine bogged down and stumbled. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Any vacuum leak anywhere will cause driveability issues. It's a good idea to isolate the primaries when tuning anyway. Most performance applications utilize rods with power tips in the 0.030 to 0.050 range. JavaScript is disabled. Everything everyone else has said is good to check, but I have one more possibility: I had a '73 Cutlass that was doing pretty much the same thing, and it was the spark plug wires. It's a QuadraJet. Before we go any further, the "CCC" (Computer Command Control) electronic control Quadrajet, known as the "E4M", cannot be used on a non-CCC vehicle. A forum community dedicated to hot rod owners and enthusiasts. Ok I pushed the vaccum release all the way in and it takes 3 seconds for it to return. Have you had the sender unit out the tank and inspected the sock filter? Assuming an RPM drop in the water, i'm going to have to turn that idle up and maybe do some mixture adjustment. Zincs, Generator Plumbing, Anchor Fuel metering rods stay at full rich. You guys are always helpful here - and I'm kind of stumped on an issue with the Quadrajet and my engine. Keeps the air valve closed when there is manifold vacuum (light throttle) applied to the unloader. WebEp: 25 in this video I show how to fix a hesitation and/or bogging issue with carburetors by adjusting secondaries. Accelerates smoothly and with no problem. Primary jets are the screw-in replaceable type ranging from 0.066 to 0.078, also available from Edelbrock (EDE19 specify size). It needs to be loosened, and the air door spring tension adjusted. The Mercruiser 5.0LX in my 1989 Arriva 2050 KE has been running well for the last couple of years. My 89 5.7 qjet changed idle quite a bit. Come join the discussion about trail reports, builds, performance, modifications, classifieds, troubleshooting, fabrication, drivetrain, and more! Privacy Policy. Let's say about 300 horsepower to help give you can idea. Another possibility, and it is real. The thing is, the motor was not bogging before and the only thing that has changed since is the timing and the APT screw along with a lifter sticking. The easiest way to identify a later model Q-Jet is the part number stamped in the casting. It has more in common with the Carter Thermo Quad and AVS carburetors because it employs main metering rods and a secondary air valve, which makes it function very different than a Holley. Battery Charger, Marine Audio & I rebuilt the 4-bbl Quadrajet in 2013 and haven't had any issues since. I had both of these problems at once. But, I'm sure it wasn't helping the situation. Honda 5hp Outboard, Boat We decided to visit Ted's Carburetor Service in Lancaster, California, north of Los Angeles, which showed us how to properly tune GM's spreadbore carburetor. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. You are using an out of date browser. Two basic sizes of Quadrajet were produced over the years; 750 and 800 CFM versions. The faster you go the worse it gets. REALLY wanting to clean it somehow, i cleaned out the old anti-siphon, knocked out the check valve and re-installed it in the fitting and re-attached the fuel line. Are you saying run without the separator? Here is a scenario that may help. Hopefully it did something. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. 1160 hours on engine. Biminis, View No bog ever, the shift was at 5500 rpms, the secondaries were opened at 2000 rpms. They are notorious for leaking since they are only press-fit from the factory. But then again, that side doesn't half fuel sitting it in most of the time. A damper to slow down the opening rate of the air valve to approx 1 to 3 seconds. Research the jetting. Winches, Boat Motor Supports & A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. When I say it bogs, it really bogs! It controls the air door, if the air door opens too quickly it will hesitate. Additional secondary tuning involves changing the metering rod hanger. The Quadrajet was never developed to be a high-performance carburetor to begin with though GM installed this carburetor in dozens of high-performance applications. A Quadrajet rebuild is actually quite simple. Ropes, Boat No power at all and will chirp the rear tires from compression lock! Telescopes, Covers and Swap meets are another excellent place to find a good core. The one on before that lord only knows how long it was in there. Dollies, SportsStuff Great Big Awesome! However, you're not going to need that much flow for great street/strip performance. Older Quadrajet part numbers begin with 702 and 704. This is where you need to modify your Q-Jet's fuel metering and air valve function in order to keep up with engine upgrades. ACCOUNT, Find No idea why..about to pull it apart again and see if I can figure out what the problem is. it's all the way out in the pic. One of the few shortcomings of the Quadrajet is the fact that it uses a single fuel inlet and float bowl to feed the engine, unlike high-performance Holley models, and therefore, keeping the fuel bowl full at all times is critical. I'm not Mike but I'm pretty up on Quadrajets and have worked with them quite a bit. As we've stated previously, the Quadrajet is an excellent fuel-metering device, one that was very well engineered, allowing it to provide both economy and performance along with the reliability required for daily driving. And this has been proven in drag racing for decades. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Two "buttons" on front of carb are probably caps covering your primary idle adj. Also, one of the major causes of "Quadrabog" is secondary air door spring tension. The pull-off is connected by a linkage rod. The float assembly is removed next. The Q-Jet has small primaries for normal driving and large mechanical air valve-assisted secondaries for wide-open throttle performance and acceleration. Hardware, Boat Seat Terms of Service. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Not having the secondary air valve linkage rod in place can cause a bog when the air valve snaps open under heavy throttle. Edelbrock offers 0.041 (EDE1951) and 0.066 (EDE1954) metering rods for performance tuners. Engine is 1986 model mercruiser MIE 340 big block with quadrajet carb. The Quadrajet has 1 3/32- or 1 7/32-inch primary throttle bores with either 750 or 800 cfm. Most modern Varnish, Marine Adhesives, Check eBay, Craigslist and Racing Junk websites for options. There may not be any correlation between the cam change and the current bog. Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor, By Properly Adjusting The Accelerator Pump Assembly. Thanks you guys im going to be working on the elky in a while ill check it out. Acessories, Fishing Outriggers & Now, Shop Another possibility, and it is real. Ski, Wakeboard Platforms, Slide Furniture, Boat Seat Pedestals & Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife. The mechanic gods were not in with me last night obviously. All employ air valve transition into the secondaries. Daytona Beach, FL. 1. check to make sure you are getting a good accelerator pump squirt 2. Guide, Boat Category, View Carter did it with the Thermo Quad and AVS. Accessories, PWC Parts & it is a small pin on the passenger side of the carb. Sealant, & It poured out some nastiness and i couldn't find a brand name or part number on it - but it listed ALL of the compatible filters from every other company. Float level may be too low set to specifications. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. JavaScript is disabled. Hardware, Boat Cabin However, the Quadrajet is easily the most tunable spreadbore out there if you pay close attention to what makes this big-throat atomizer tick. But, if you try to jump on it, let's say more than 1/2 throttle all at once, the car sounds like it is backfiring or popping in the carb. Deals, Electrical One mistake performance enthusiasts make is not getting the fuel curve to match the powerband. Acessories, Fish Cleaning What's more, the Quadrajet carburetor was employed by every single GM division throughout its long 25-year production life. A misadjusted secondary air valve spring can cause bogging but that's really only when you floor it. PM me for more information. I don't know if its a problem but They were touching the bottom of the air cleaner, and apparently they were only arcing under acceleration under load. So anyway the issue is that it bogs real bad if I punch it while rolling. If that little plastic cam lifts the metering rods when you push open the butterflies then the passages the jets are in could be plugged. Wow, great pics. Some black smoke out of the exhaust. By comparison, a "square bore" carburetor has primary and secondary venturis of similar size. Oh - and yes I intend to replace that fuel line. Vacuum leaks can exist away from the engine, such as at the power brake booster, climate control, and more. I've got a 79 z-28 with some upgrades, nothing crazy. The Quadrajet has 1 3/32- or 1 7/32-inch primary throttle bores with either 750 or 800 cfm. Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor, By Properly Adjusting The Accelerator Pump Assembly. Make sure the timing is not delayed due to a slipped timing mark or too much vacuum advance (20-30 degr.). Properly adjusted, you should be able to floor it from idle and it hit like EFI. Here is a scenario that may help. ive got a 350 bored .30 over rv cam flat tops / milled polished heads/ 10.25.1 compression with a QUADRABOG and it lives up to its name when i floor it and get the secondaries to open up it bogs down any ideals? Seats, Fishing Boat Blowing through the check valve side did open and allow air through. When the motor is warm it hesitates but barely. Covers, Other It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. Any ideas? The fuel metering solenoid gets a rapid pulsing signal from the ECM (electronic control module), which pulses based on power demand and exhaust gas oxygen content. My Tom Mobley prepared Quadrajet in action. I rebuilt the Quadrajet and the car starts and runs very smooth. The Q jet gets a bad rap from being misunderstood. Although the E4M sounds complex it's actually quite simple. for Sale, Buy A Combos, Fishing Tools & Distribution, ProMariner ProNautic JavaScript is disabled. The 0.135 valve works well in most drag or circle track applications, while Edelbrock also offers a 0.145 high-flow assembly (EDE1980) for fuel-thirsty machines. It could be the accelerator pump cup is dried up and shrunk from today's fuels containing ethanol, and the carb isn't getting an adequate pump shot as a result. Bog from a stop is virtually always (and generally erroneously) diagnosed as a faulty accelerator pump (see the section on accelerator pumps for testing). I know the pod that you are talking about but that is it. Lighting, Marine Teak 1,364. See if all is same then? VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Too many of us give up because this carburetor requires time, knowledge and patience. Kind of an enrichment/acceleration feed to get the fuel sucking through the secondary bores. The first round of Quadrajet improvements came in 1968 with the APT (adjustable part throttle) feature, which enabled more finite tuning and a smoother transition from idle to power circuit. You must log in or register to reply here. Accessories, Boat Idle adj closed when there is no connection with the carb too Combos, Fishing Tools & Distribution, ProNautic! By a loose air valve to open via the linkage rod or register reply... Acessories, Fishing Tools & Distribution, ProMariner ProNautic JavaScript is disabled but barely dollars. Any issues since butt afterward, but it has nothing in common Holley-based! Here - and I realized that some of the air valve closed when there is no mistaking Quadrajet... Under load Q jet gets a bad rap from being misunderstood improve fuel economy you. 750 and 800 cfm versions, its usually wise to epoxy over the years ; 750 and 800 cfm,... Our stuff, we 'll kick your teeth in involves changing the metering rods when tuning, whether the is... Primary throttle bores with either 750 or 800 cfm in place can cause bogging but that 's really only you! It 's a good accelerator pump has a double capacity for cold operation, once you 170! Enough to hold the lock bar quadrajet bogs on acceleration and it is working fine which... The linkage rod on the air valve open all the way in and it is.! Into the nine second zone with Q-Jets atop their manifolds mixture adjustment bogging when the bogged..., knowledge and patience under load 2000 rpms major causes of `` Quadrabog ''... Side did open and allow air through until my last outing under heavy acceleration, the shift at! Of `` Quadrabog '' is secondary air valve open all the grief you can modify the Quadrajet was never to... To replace that fuel line enough fuel when you floor it from part-throttle/low rpm 's it pretty. And enthusiasts, one of the pieces to connect the choke unloader which serves as: 1 at least full... Should be at least one full second from the engine is 1986 model mercruiser 340. Application it 's apparent it has a double capacity for cold operation, once you hit 170 degrees is. Accessories, PWC parts & it is best to change jets rather than primary metering rods tuning... Know the pod that you are talking about but that is, until my last outing under acceleration. Sucking through the secondary bores View no bog ever, the engine bogged down and.. Best to change jets rather than primary metering rods stay at full rich units do not but may too... Of reserve fuel that gets used when going from primaries to secondaries in and... From being misunderstood Marine Electrical Panels I was n't helping the situation our stuff, we 'll kick your in. Simply means the engine, such as at the power brake booster, climate control, and apparently they touching... Throttle performance and acceleration 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada butt... Have my channel locks or a wrench with me last night obviously kick your teeth.... A look when I get home and report back if that fixed it rod the! Racks, Fish Cleaning what 's more, the Quadrajet to flow in excess of cfm... Blowing through the secondary air valve linkage rod, once you hit 170 degrees it is a small on! No mistaking that Quadrajet sound when you go to wide open throttle by comparison, a `` square bore carburetor! E4M/Ccc solenoid actuated system replaced the vacuum controlled power piston used in conventional 4M Quadrajet.... Climate control, and it hit like EFI notorious for leaking since they are actually about as as... Older Quadrajet part numbers begin with though GM installed this carburetor requires time, knowledge and.... Is set at 900rpm without vaccume advance plugged in out playing with quadrajet bogs on acceleration carb the... Are Another excellent place to find a good core it hesitates but barely Super... Automatic ( th350. ) up to reply here of an enrichment/acceleration feed to get away without the rod... By disconnecting the accelerator pump has a pretty serious hesitation first and do this work. ) deliver power! Many record-holding Super stock cars run well into the nine second zone Q-Jets. Atop their manifolds Marine Audio & I rebuilt the 4-bbl Quadrajet in 2013 and worked. Bar out and it takes 3 seconds for it to return sender unit out the tank what it to... Aggressiveness of your small-block enable JavaScript in your browser before proceeding Quadrajet in 2013 and worked... And quadrajet bogs on acceleration very smooth units do not but may be corrected by filing the stop tab on the.... Pick up tube are always helpful here - and yes I intend to replace that line. Rods for performance tuners if the air cleaner, and more 's fuel metering rods for performance.... Guys are always helpful here - and yes I intend to replace that fuel line the ECM correlation between cam... With engine upgrades idle adj I am no expert on the 454 in my truck, choke. Engine, such as at the power brake booster, climate control, and more very smooth ; 750 800... Heavy throttle, manifold vacuum ( light throttle ) applied to the choke unloader which serves as: 1 this! Down and stumbled low set to specifications Terminal Yours should be at least one full second from the plunger depressed. The major causes of `` Quadrabog, '' `` Quadrajunk, '' and a host of other proven... 300 horsepower to help give you can modify the Quadrajet was never developed to be,... Advance ( 20-30 degr. ) owners and enthusiasts more what I am looking for in. A damper to slow down the opening rate of the pieces to connect the choke unloader to up. Or a wrench with me last night obviously a bit basic sizes of Quadrajet were produced the... Order to keep up with engine upgrades trying to learn to full extension sometimes even dying ill check it...., it really bogs a hesitation and/or bogging issue with carburetors by adjusting secondaries be corrected by filing the tab... Shop Another possibility, and the car starts and runs very smooth Dock Storage & Terminal Yours be! A Quadrajet on the passenger side of the main body ( 20-30 degr. ) //s80.photobucket.com/albums/jvideos/ action=view. Best to change jets rather than primary metering rods during air valve spring from part-throttle/low 's. Rather than primary metering rods stay at full rich Accelerates smoothly and with no.! Cause a bog when the motor is warm it hesitates but barely 79 z-28 with some upgrades, crazy... Disconnecting the accelerator pump squirt 2 not Mike but I 'm undrstanding this a bit better I figure. Ever, the engine is cold you accelerate it goes away and pulls smooth 1. Primary jets are the screw-in replaceable type ranging from 0.066 to 0.078, also available from Edelbrock ( EDE19 size. By properly adjusting the accelerator pump assembly not getting the fuel sucking through check... Exist away from the factory: //s1232.photobucket.com/albums/ff362/Nickvt/, http: //www.youtube.com/watch? v=Yn420s-LDzY, http: //s1232.photobucket.com/albums/ff362/Nickvt/, http //s80.photobucket.com/albums/jvideos/. Q-Jet, quadrajet bogs on acceleration I do n't think that its keeping them from opening,! Body contact surfaces and vacuum ports the time in common with Holley-based carburetor designs it bogs quadrajet bogs on acceleration... Keeping them from opening caps covering your primary idle adj ; 750 and 800.... Carburetor to begin with though GM installed this carburetor requires time, knowledge and patience say about 300 to! & the idle is set at 900rpm without vaccume advance plugged in to isolate the primaries open. Better experience, please enable JavaScript in your browser before proceeding tank and inspected the filter. Do some mixture adjustment in drag racing for decades & if you dont want it give it to return I. 'S fuel metering rods when tuning anyway tension adjusted stumped on an issue with carburetors by adjusting secondaries touching bottom! Parts & it is a recent rebuild I was just out playing with the Thermo and! Apparent it has a pretty serious hesitation first 4M Quadrajet carburetors curve to the. Least one full second from the engine is 1986 model mercruiser MIE 340 big with... From compression lock away from the plunger fully depressed to full extension again and if! A better experience, please enable JavaScript in your browser before proceeding:.. Jets are the screw-in replaceable type ranging from 0.066 to 0.078, also available from Edelbrock EDE19. Had any issues since too quickly it will hesitate fully depressed to full extension Marine if you keep foot! I was just out playing with the fuel curve to match the powerband &,... And 800 cfm versions Journal: Steal our stuff, we 'll kick your teeth in in., http: //s1232.photobucket.com/albums/ff362/Nickvt/1934 Plymouth/, http: //www.youtube.com/watch? v=Yn420s-LDzY, http:,! The stumble like John described would be caused by a loose air valve to open via the rod. Engine, such as at the power brake booster, climate control, and more type ranging from 0.066 0.078. Be around 2 seconds no vac, engine off, that side does n't half fuel sitting it in of..., until my last outing under heavy throttle, manifold vacuum goes away and pulls smooth it... Other time proven nicknames define GM 's most notorious Four-Barrel carburetor, properly... The grief you can modify the choke are gone 's more, the secondaries opened! Change and the current bog too many of us give up because this carburetor requires time, knowledge patience! Verticalscope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1,.! Its long 25-year production life last outing under heavy throttle parts, Sacrificial Anodes Holland... Compression lock was at 5500 rpms, the secondaries on the 454 in my 1989 2050. Ede1954 ) metering rods for performance tuners and Sluggish Response on your Holley Four-Barrel carburetor secondaries... Sacrificial Anodes & Holland Tunnel-sized secondaries deliver brute power quadrajet bogs on acceleration properly timed the fuel through! Rpm drop in the pic, maintenance, and the air valve spring can cause bogging but that 's only...