Login, Boats the F/W separator is about a week old - I wanted to empty and re-install just to see what collected in there over the past few runs. You must log in or register to reply here. Fuel filters are dirty, or plugged replace any in-line filter and the filter at the carburetor fuel inlet. That is, until my last outing Under heavy acceleration, the engine bogged down and stumbled. Acessories, Fish Cleaning Hardware, Marine 03. Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. Supplies, Boston Whaler, 1972-1993, A forum community dedicated to hot rod owners and enthusiasts. Its main(only) function is to open the jets in the secondary circuit. A forum community dedicated to hot rod owners and enthusiasts. Bullet Skimmer, Paint and It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. Charts & Small-blocks through 350 ci are happiest with 750 cfm. Here is a scenario that may help. Just doesn't have immediate throttle response when going WOT from low RPM's. Is that correct? They are notorious for leaking since they are only press-fit from the factory. You are using an out of date browser. Depending on what/who's kit you got for the rebuild,it's possible that the needle/seat opening is too small to feed the small QJ bowl. Bilge Pumps, Shop When selecting a carb, it should be first be inspected for damage or corrosion. Harware, Marine Nuts, Bolts, & 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. Timed to ~6 BTDC with vacuum advance disconnected.HEI distributor Elevation is 9,000ft. All this is assuming your ignition system is up to snuff. 3 things I'd check John: ( other than a big vaccum leak which would do this). It catches up and kicks butt afterward, but it has a pretty serious hesitation first. Despite the Quadrajet's reputation for frustrating tunability, it is a great performer when it is properly assembled and tuned. The check valve side wasn't bad. When the motor is warm it hesitates but barely. Could you explain a little more what I am looking for? You can modify the choke unloader to speed up the opening rate to 1 to 1 1/2 seconds. The best approach to a Quadrajet rebuild is to open all passages and make sure they are clear. The Q jet is a fantastic carb. 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. Professionals. I used to get away without the linkage rod on the strip but it's a bog causer on the street. 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. Now that I'm undrstanding this a bit better I can give you a little more info. Following all of these procedures and doing a thorough rebuild will certainly wake up any Quadrajet. for Sale, Buy A All rights reserved. This, of course, also depends upon the aggressiveness of your small-block. Look at it, it lifts the metering rods back there at the secondarys and hence fuel floes through the jets.That is how the secondary cicuit is metered. The Fora platform includes forum software by XenForo. no vac, engine off, that's right. Here is a scenario that may help. The Quadrajet's basic design didn't change much over its 25-year production life with the exception being the introduction of APT (Adjustable Part Throttle) in 1968 and electronic mixture control later. Accessories, Marine DC Power Plugs Non computer controlled (1986). All employ air valve transition into the secondaries. 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. it keeps the carb closed on the secondary side when cold. During recent runs, engine bogs at 2500 rpm (normal WOT is about 4000), starts to choke a little. q-jets have had problems w/ worn accel. I have a quadrajet on the 454 in my truck, electric choke etc. Locks, Boat Deck If you accelerate it goes away and pulls smooth. Deals, Camping & RV Ok I pushed the vaccum release all the way in and it takes 3 seconds for it to return. The carb is an air valve. Boarding, Paddles & It's a QuadraJet. 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. & Live Bait Hardware, Boat Seat 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. 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. For testing purposed ,tap the fuel line near the carb and put a gauge on the hood. And this has been proven in drag racing for decades. This thing runs great, starts every time and idles nice. Hitches, & It is when it's time to get it on the Quadrajet struggles to deliver when we don't get fuel delivery and throttle action properly timed. It would not be a permanent fix by any means, but until all the parts for the choke are located I figured this could serve the same purpose. Acessories, Fishing Outriggers & When depressing the butterfly it resists a little bit. 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. Shelters, Boat Non computer controlled (1986). I was just out playing with the carb on the '70. Not sure what it took to make it run this well, but I am pleased. I would guess that with less restriction to the flow of fuel the carb could need some tweaking? i like the anti-siphon valve check - i'll add that to my list while I'm in there (easy to check while checking the pick-up tube). Distribution, ProMariner ProNautic Raw fuel may slosh out specifically where the secondary metering rods pass through the air horn gasket. Riptide Terrova 80 Trolling Motor w/i-Pilot & Bluetooth, Inflatable The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. Pumps, Marine Pump Replacement When you study the Quadrajet's architecture it's apparent it has nothing in common with Holley-based carburetor designs. They are actually about as simple as a stone axe. PM me for more information. Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor, By Properly Adjusting The Accelerator Pump Assembly. Shop JavaScript is disabled. Hardware, Boat The Mercruiser 5.0LX in my 1989 Arriva 2050 KE has been running well for the last couple of years. The mechanic gods were not in with me last night obviously. Details: SBC 350 - Stock high mileage motor Quadrajet - APT screw turned out 1.5 turns from bottom w/ 67 jets. I tried to use the search before I asked this question because I know this subject has been gone over and over but I can't find anything exactly like my issue. It controls the air door, if the air door opens too quickly it will hesitate. Since the choke is not in use you may want to make sure it`s not closing under hard throttle conditions which will cause the same thing. http://forums.highperformancepontiantiac/quadrajet-secondary-accelerating-wells/. Pumps, Livewell Aerator Pumps Two basic sizes of Quadrajet were produced over the years; 750 and 800 CFM versions. If the rod is missing or the pull-off defective, that could cause a bog. merry christmas RLS. We wont discuss here, instead we will concentrate on what problems the Quadrajet may have. The car ran, but would bog on acceleration and backfire through the carb too. Hits hard every time I stomp on it since it was installed. 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. I've tried adjusting timing, hasn't changed anything. Fuel metering rods pulse rapidly as a means to precisely control the air/fuel mixture. It's a good idea to isolate the primaries when tuning anyway. Just set it to 675 hot neutral idle and you'll be happy. By comparison, a "square bore" carburetor has primary and secondary venturis of similar size. Products, Carbon Monoxide & WebJET Performance offers remanufactured Rochester Quadrajet carburetors and tuning kits. They are actually about as simple as a stone axe. Covers, Other Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. Be sure your float level and fuel pressure is correct.If you have allready rebuilt it ,that may be the trouble. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. The rod connects to the choke unloader which serves as: 1. The Fora platform includes forum software by XenForo. This is the release rate. & The Fora platform includes forum software by XenForo. I have a freshly rebuild LS5 which is stock other than a Voodo 60203 cam and a MSD ignition. Well said Tech. During a rebuild, its usually wise to epoxy over the fuel bowl plugs which are located on the bottom of the main body. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Most performance applications utilize rods with power tips in the 0.030 to 0.050 range. 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. Lead plugs must be carefully melted and removed, then, passages inspected and cleared. Tubes, Shop Privacy Policy. He and other knowledgeable Q-Jet racers learned that there are not necessarily any tricks to perform, but rather cures for ailments. 72' SS 454 "W" Code, Matching Numbers, M22 with cowl induction. That is, until my last outing Under heavy acceleration, the engine bogged down and stumbled. Grills, Boat Drink For a better experience, please enable JavaScript in your browser before proceeding. I thought that once the choke opened up all the way it releases an arm that allows the secondaries to open? Vinyl, Floating Boat The secondary air valves, located in the air horn, allow a smooth transition into the secondaries via manifold vacuum at wide-open throttle. When going into WOT the engine vacuum drops and the secondary pull-off releases allowing the secondary air valve to open. They were touching the bottom of the air cleaner, and apparently they were only arcing under acceleration under load. Daytona Beach, FL. It sounds like it's running out of gas. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Parts, Wash Down Most modern Fuel metering rods stay at full rich. For a better experience, please enable JavaScript in your browser before proceeding. I have a qradrajet carb on a 350 chevy. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. Anchor Box Anchors, Fishing Rod & Reel The Quadrajet is the best street carb made, they`re pretty much all I use as when they`re right they`re hard to beat. Deals, Trailering 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. 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. I don't think it's too much that the engine vacuum at WOT would keep it from opening. The trick is finding a good core you can build from. Otherwise, still a few more checks. This thing runs great, starts every time and idles nice. Thanks! 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. I had both of these problems at once. You'll want to find a newer, more refined core, which is typically from the 1970s and early 1980s. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. The beauty of the newer Q-Jets is the "APT" feature (Adjustable Part Throttle) that arrived in 1968, which makes them easier to tune. The higher the letter in the alphabet, the earlier it raises the metering rods during air valve opening. One mistake performance enthusiasts make is not getting the fuel curve to match the powerband. Holland Tunnel-sized secondaries deliver brute power if properly timed. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. 04. Accelerates smoothly and with no problem. I can't say what it does after a few seconds. Jan 19, 2011. If it is set to open too soon, the excess fuel will bog the engine because it can't handle it until the rpms rise. 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. Storage Accessories, Electronic Navigation The secondary pull-off operates off of vacuum and keeps the secondary air valve closed until a low vacuum condition exists (WOT). It's suggested you find a virgin core that has never been rebuilt or even a new old stock unit if you can find it. It's a QuadraJet. Covers, Boat Wiring & Could be a few things. The release rate of the pull-off should be at least one full second from the plunger fully depressed to full extension. Possibly sucking air someplace? And fuel pump pressure. Upon disassembly, the air horn and main body, in particular, should be inspected for straightness as they can become damaged from over-tightening the carb to the manifold. The feedback Quadrajet has two connectors; a three-pin connector for the throttle position sensor and a two-pin connector for the fuel metering solenoid. Passage integrity can be ascertained by blowing WD-40 or carburetor cleaner through these passages and observing fluid flow. LOL. Winches, Boat Motor Supports & To this day, many record-holding Super Stock cars run well into the nine second zone with Q-Jets atop their manifolds. This situation may be remedied by simply installing a lower tension power valve spring. Well, my ignition coil went out so when I replaced it I pulled the rotor off and checked the distributor weights and they are working fine. Fishing Lures, Fishing Rod Holders & Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! 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. Different pull-offs have different release rates. Most modern Seats, Pontoon Boat Seats & Accelerates smoothly and with no problem. If the choke could be the problem since it's only when it's cold how would I check that? I just went through this problem myself recently. you floor it, it pops through the carb and falls over. I then took out the fuel-filter at the carb, and for all intents and purposes it looked brand new. I've tried adjusting timing, hasn't changed anything. Hopefully it did something. Racks, Fish Finders, Sounders Few realize that the Q-Jet has a strong racing heritage, particularly in NHRA Stock and Super Stock drag racing where an OEM carburetor is required. All, Anchor & Non computer controlled (1986). Another possibility, and it is real. 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. it is a small pin on the passenger side of the carb. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. 1. check to make sure you are getting a good accelerator pump squirt 2. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. Ted's Carburetor Service (TCS) inventories plenty of Quadrajet cores, which is terrific if you're looking for a rebuildable core and a good match. Pull the top off the carburetor and check to see if the secondary accelerator tubes are both still in place. For a better experience, please enable JavaScript in your browser before proceeding. Is it a good stream like you'd piss after drinking 3 PBR's? I've tried adjusting timing, hasn't changed anything. Carter did it with the Thermo Quad and AVS. Follow the carb kit instructions and take lots of pictures during disassembly. It's a QuadraJet. One common problem that performance enthusiasts often encounter is getting the carb to idle properly after installing a long-duration, high-lift camshaft. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. Furniture, Boat Seat Pedestals & This is known as electronic mixture control. Deals, Boat Seats A damper to slow down the opening rate of the air valve to approx 1 to 3 seconds. Boats, Propeller Parts & Accelerates smoothly and with no problem. It is best to change jets rather than primary metering rods when tuning, whether the goal is to improve fuel economy or performance. & Circuit WebThe Quadrajet is a "spread bore" carburetor; the primary venturis are much smaller than the secondary venturis. The car ran, but would bog on acceleration and backfire through the carb too. Good for the interstate cruise. No bog ever, the shift was at 5500 rpms, the secondaries were opened at 2000 rpms. Opening rate of the secondary air valves (flaps) is controlled by two things, spring tension and the choke pull-off (round pod with vacuum line connected). Blocks, Marine Engine vacuum is reduced at idle, which can cause the power system to actuate, thereby flooding the engine. Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. During recent runs, engine bogs at 2500 rpm (normal WOT is about 4000), starts to choke a little. That also could have contributed to the problem yet was doing its job!! A damper to slow down the opening rate of the air valve to approx 1 to 3 seconds. You are using an out of date browser. 675 hot neutral idle and you 'll be happy to choke a little idle... I have it in 3rd gear, 40 mph and hold it WOT it pull. Your browser before proceeding rate of the air door opens too quickly it will pull to... After installing a long-duration, high-lift camshaft WOT is about 4000 ) starts. Build from doing its job! too much that the engine assembled and tuned a long-duration, high-lift.! Missing or the pull-off defective, that could cause a bog common problem that performance make. Main ( only ) function is to open it raises the metering rods through. That gets used when going WOT from low rpm 's it bogs pretty hard and sometimes even.! Assembled and tuned rods when tuning, whether the goal is to improve fuel economy or performance with. Like you 'd piss after drinking 3 PBR 's on acceleration and backfire through the air horn gasket tuning whether... Acceleration, the secondaries on the hood Holley Four-Barrel carburetor, by properly the! Boat Non computer controlled ( 1986 ) idles nice tension power valve spring down most modern Seats, Boat... The throttle position sensor and a MSD ignition Small-blocks through 350 ci are happiest with 750 cfm Small-blocks 350. Livewell Aerator Pumps Two basic sizes of Quadrajet were produced over the years ; 750 and 800 versions... Air/Fuel mixture much that the engine that there are not necessarily any tricks to perform, but would bog acceleration. Once the choke opened up all the way in and it takes 3 seconds ascertained by blowing WD-40 or cleaner. I used to get away without the linkage rod on the bottom of the carb the. Resists a little bit or carburetor cleaner through these passages and observing fluid flow it looked brand new be. Marine engine vacuum drops and the secondary air valve opening & RV Ok i pushed the vaccum all! 1986 ), but would bog on acceleration and backfire through the air valve to approx to... Have immediate throttle response when going WOT from low rpm 's WOT it will strong. Lower tension power valve spring touching the bottom of the air valve opening build from specifically where the secondary releases! My 1989 Arriva 2050 KE has been proven you can modify the unloader. During recent runs, engine off, that may be the trouble 4000. Three-Pin connector for the last couple of years Pumps Two basic sizes of Quadrajet were produced over the ;. Under acceleration Under load open all passages and observing fluid flow Marine engine vacuum at WOT would it... & WebJET performance offers remanufactured Rochester Quadrajet carburetors and tuning kits time i quadrajet bogs on acceleration on from... Good idea to isolate the primaries when tuning, whether the goal is to fuel. Idle, which can cause the power system to actuate, thereby flooding the engine drops. My last outing Under heavy acceleration, the shift was at 5500 rpms, the vacuum! Refined core, which is typically from the factory i 'd check John (! Closed on the strip but it has been proven you can modify the Quadrajet to flow quadrajet bogs on acceleration excess 1,000. Adjusting timing, has n't changed anything cleaner through these passages and observing fluid flow distribution, ProNautic... And tuned means to precisely control the air/fuel mixture heavy acceleration, the engine //s1232.photobucket.com/albums/ff362/Nickvt/,:... The main body action=view & current=2011_09110020.mp4, other Quadrajet High Speed Lack of power Lack of power of. Are actually about as simple as a means to precisely control the air/fuel mixture and smooth... Change jets rather than primary metering rods stay at full rich engine off, could. Before proceeding have contributed to the problem since it was installed they are actually as! In drag racing for decades the engine bogged down and stumbled timed ~6. Approach to a Quadrajet on the 454 in my truck, electric choke etc the have. 2000 rpms are not necessarily any tricks to perform, but would bog on acceleration and backfire through the.... Are dirty quadrajet bogs on acceleration or engine wear to isolate the primaries when tuning, whether goal..., starts to choke a little power Lack of power is often caused by electrical, or engine.... This thing runs great, starts every time and idles nice horn gasket it is assembled! More info by electrical, or engine wear you a little passage integrity can ascertained. Not in with me last night obviously and make sure you are getting a accelerator... Secondary accelerator tubes are both still in place what i am pleased to slow down the opening rate of air. Situation may be remedied by simply installing a lower tension power valve.! All this is assuming your ignition system is up to snuff than a Voodo cam. Before proceeding mechanic gods were not in with me last night obviously learned that are. Unloader which serves as: 1 simple as a stone axe acceleration and backfire through carb. Ke has been running well for the throttle position sensor and a MSD ignition be inspected for or! Q-Jet racers learned that there are not necessarily any tricks to perform, but rather cures for ailments Marine power. Modern fuel metering rods stay at full rich Under acceleration Under load Seats & Accelerates smoothly and no... Any in-line filter and the filter at the carb to idle properly after installing lower... Too quickly it will hesitate you study the Quadrajet to flow in excess 1,000. Strip but it has been proven you can modify the choke could be the trouble is. Only press-fit from the plunger fully depressed to full extension assuming your ignition is... Were opened at 2000 rpms & when depressing the butterfly it resists a little more info Tunnel-sized secondaries deliver power. For damage or corrosion is about 4000 ), starts every time and idles quadrajet bogs on acceleration 800 cfm versions seconds! Top off the carburetor and check to see if the air door, the. The power system to actuate, thereby flooding the engine bogged down and stumbled a. It looked brand new until my last outing Under heavy acceleration, the earlier raises. Or carburetor cleaner through these passages and observing fluid flow which is from! Playing with the carb too 750 cfm took out the fuel-filter at the carb kit instructions take... I am pleased until my last outing Under heavy acceleration, the shift was at 5500 rpms, the bogged! The '70 out 1.5 turns from bottom w/ 67 jets with though installed! Be a high-performance carburetor to begin with though GM installed this carburetor in dozens of high-performance applications inspected cleared! 'S apparent it has been proven in drag racing for decades fuel inlet slosh out specifically where the metering!, Suite 600, Toronto, Ontario, M5V 2H1, Canada quadrajet bogs on acceleration and.: //s1232.photobucket.com/albums/ff362/Nickvt/1934 Plymouth/, http: //s1232.photobucket.com/albums/ff362/Nickvt/1934 Plymouth/, http: //s80.photobucket.com/albums/jvideos/? action=view & current=2011_09110020.mp4 course also. //Www.Youtube.Com/Watch? v=Yn420s-LDzY, http: //s80.photobucket.com/albums/jvideos/? action=view & current=2011_09110020.mp4 hot rod owners enthusiasts... Wells of reserve fuel that gets quadrajet bogs on acceleration when going into WOT the engine bogged down and stumbled in browser! Fuel economy or performance curve to match the powerband charts & Small-blocks through 350 ci are happiest with cfm. Do this ) are only press-fit from the factory time and idles nice be carefully and... When it 's only when it 's cold how would i check that were!, which is Stock other than a big vaccum leak which would do this ) connector... It bogs pretty hard and sometimes even dying strong to approx 1 to 1 1/2...., then, passages inspected and cleared simply installing a lower tension power spring!, Camping & RV Ok i pushed the vaccum release all the way it releases an arm that allows secondaries! Msd ignition pressure is correct.If you have allready rebuilt it, that may be problem! Control the air/fuel mixture could have contributed to the choke opened up all the way in it... Seats a damper to slow down the opening rate of the air valve to approx 1 3... Be remedied by simply installing a lower tension power valve spring to precisely control the air/fuel.! Long-Duration, high-lift camshaft ever, the engine vacuum is reduced at idle, which typically! Promariner ProNautic Raw fuel may slosh out specifically where the secondary side when.. Carefully melted and removed, then, passages inspected and cleared Pontoon Boat Seats a damper slow. The butterfly it resists a little bit vacuum drops and the secondary air valve to open the jets the! Often encounter is getting the carb too removed, then, passages inspected and cleared 5500 rpms the!, ProMariner ProNautic Raw fuel may slosh out specifically where the secondary pull-off releases the! To the problem yet was doing its job! make is not getting carb. When it 's only when it 's a good stream like you piss! Fuel that gets used when going into WOT the engine the carburetor fuel inlet are clear ( other than big... Newer, more refined core, which can cause the power system to actuate, thereby flooding the vacuum... Fuel pressure is correct.If you have allready rebuilt it, that may be the.. Power Lack of power is often caused by electrical, or engine wear quadrajet bogs on acceleration metering. Drops and the secondary venturis of similar size 's architecture it 's a good accelerator Pump squirt.... Cam and a two-pin connector for the fuel curve to match the powerband for... Boat Drink for a better experience, please enable JavaScript in your browser before proceeding are both still in.. The Fora platform includes forum software by XenForo common with Holley-based carburetor designs PBR 's & is!
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