Parts, Wash Down Screws, Boat Handles, Pulls, 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). Additionally, as the secondary air valve opens, the secondary metering rods are raised out of the secondary metering orifices. Disassembly of this Q-Jet begins by disconnecting the accelerator pump arm, choke assembly and all air horn screws. Acessories, Fish Cleaning Boats, Propeller Parts & Petite primary bores keep fuel consumption to a minimum. A forum community dedicated to custom off-road vehicle owners and enthusiasts. Fuel metering rods pulse rapidly as a means to precisely control the air/fuel mixture. 04. PM me for more information. Wells, Toilet & Waste Good Racers Dont Skimp on Safety Equipment. This thing runs great, starts every time and idles nice. Keeps the air valve closed when there is manifold vacuum (light throttle) applied to the unloader. Ventilation, Interior & Cabin We wont discuss here, instead we will concentrate on what problems the Quadrajet may have. Hangers are identified by letter stamping, offered in increments from B to V. Insurance, Boat The Fora platform includes forum software by XenForo. On the other hand, if the valve doesnt open quick enough to meet the engines air/fuel demands, the engine will not accelerate to its potential. I then took out the fuel-filter at the carb, and for all intents and purposes it looked brand new. If it's working OK but just releases too fast, a restrictor can be made to put in the vacuum line to the pull-off. My 89 5.7 qjet changed idle quite a bit. Handles, Life Jackets & Meters, Marine Electrical Panels Make sure the dist vacuum advance is connected to full manifold vacuum. See if all is same then? & Tubes, Shop By comparison, a "square bore" carburetor has primary and secondary venturis of similar size. However, you're not going to need that much flow for great street/strip performance. Small-blocks through 350 ci are happiest with 750 cfm. Detectors, Binoculars & The higher the letter in the alphabet, the earlier it raises the metering rods during air valve opening. Systems, Lowrance Hook2-4 GPS No power at all and will chirp the rear tires from compression lock! http://www.73-87.com/7387garage/drivetrain/myqjet.htm. Did you know Ford ran the Quadrajet on its 1970-'71 429ci big-blocks. 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 have a quadrajet on the 454 in my truck, electric choke etc. pump ck. Shelters, Boat Not having the secondary air valve linkage rod in place can cause a bog when the air valve snaps open under heavy throttle. Daytona Beach, FL. Considering the carb is a recent rebuild i wasn't really surprised. Parts, Rule 1500 GPH Automatic Combos, Fishing Tools & JavaScript is disabled. 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. 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. & Rings, Prop Nut Kits & Hardware, Boat Cabin GPS Chartplotter and Fish Finder Combo, Find Take it apart and lightly sand-clean it. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Primary jet size is commonly in the 0.068 to 0.075 range. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. Could be a few things. This design is not unique to the Quadrajet. Here is a scenario that may help. What's more, the Quadrajet carburetor was employed by every single GM division throughout its long 25-year production life. New motor with only 350 miles on it so I'm trying to be nice to it. 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. Fuel filters are dirty, or plugged replace any in-line filter and the filter at the carburetor fuel inlet. Some race enthusiasts go to the extent of epoxying a fine screen on the air horn gasket, or place baffling in the float bowl to help control fuel slosh. Hello i have a 1967 el camino 327 small block with a rochester quadrajet carb and a turbo 400 trans. Seats, Fishing Boat Terms of Service. Motors, Fishing Downriggers & Forums, Find For a better experience, please enable JavaScript in your browser before proceeding. Two basic sizes of Quadrajet were produced over the years; 750 and 800 CFM versions. Kind of an enrichment/acceleration feed to get the fuel sucking through the secondary bores. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Another possibility, and it is real. I've thought about that and there is no connection with the fuel level in the tank. 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. We wont discuss here, instead we will concentrate on what problems the Quadrajet may have. Convenient when it's time to pin the butterflies. I fixed the accelerator pump and started it but it was still bogging. Oars, Wakeboard, Wakesurf & That was in park as it's an automatic(th350.). Additional secondary tuning involves changing the metering rod hanger. John, that isn't by any chance Escondido, California is it? It needs to be loosened, and the air door spring tension adjusted. So whether or not that was causing my issue or not, i dont know. 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. 03. Trolling Motors, Shop I am no expert on the Q-jet, so I'd like some thoughts on adjustment. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. 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. This situation may be remedied by simply installing a lower tension power valve spring. That is, until my last outing Under heavy acceleration, the engine bogged down and stumbled. 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. Rollers, 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. The rod connects to the choke unloader which serves as: 1. They are actually about as simple as a stone axe. At heavy throttle, manifold vacuum goes away and the unloader relaxes, allowing the air valve to open via the linkage rod. When the motor is warm it hesitates but barely. See more Reply Save Like 2 2old2fast Good for the interstate cruise. Galley, Covers and Accessories, Pontoon Bimini Vacuum leaks can exist away from the engine, such as at the power brake booster, climate control, and more. If I step on it from part-throttle/low rpm's it bogs pretty hard and sometimes even dying. Here is a scenario that may help. 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. Accessories, Electronic Navigation 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. When the motor is warm it hesitates but barely. All employ air valve transition into the secondaries. Biminis, Paint and Lights, Boat Trailer A forum community dedicated to hot rod owners and enthusiasts. JavaScript is disabled. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. 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. The Bog simply means the engine is not receiving enough fuel when you go to wide open throttle. Hitches, & Another important issue with Quadrajets is carburetor sizing. Caulking, Marine Engine It was produced in many forms, including electronic-control from 1980-'90, for a wide variety of GM applications. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! That 2nd paper carb filter is best- filters better!! But damned if i didn't have my channel locks or a wrench with me big enough to hold the lock nut. Acessories, Fishing Outriggers & Could you explain a little more what I am looking for? Test this pump for fuction at the sensor and pump. The Fora platform includes forum software by XenForo. All performance applications should ensure that the air valve opens to a full 90. Accessories, Marine DC Power Plugs Switches, Shore Power & AC Details: SBC 350 - Stock high mileage motor Quadrajet - APT screw turned out 1.5 turns from bottom w/ 67 jets. it's all the way out in the pic. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. 3. Tops, Other All, Boat Bimini Not sure what it took to make it run this well, but I am pleased. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Engine is 1986 model mercruiser MIE 340 big block with quadrajet carb. Along with a good timing curve, is the choke vacuum pull-off set-up correctly or hooked up. Also, I'm not 100% on what RPM I should time it at. Timed to ~6 BTDC with vacuum advance disconnected.HEI distributor Elevation is 9,000ft. You must log in or register to reply here. I checked the lock bar out and it is working fine. Non computer controlled (1986). The choke unloader opens the choke to a certain opening when manifold vacuum is applied at engine start. 72' SS 454 "W" Code, Matching Numbers, M22 with cowl induction. All, Anchor & Savers, Boat Trailer Guides & The secondary pull-off operates off of vacuum and keeps the secondary air valve closed until a low vacuum condition exists (WOT). Check yours by pushing it all the way in and count the seconds that it takes to come all the way back out. One of the most common ailments of a Quadrajet is hesitation after the throttle is winged open under load. If the rod is missing or the pull-off defective, that could cause a bog. We will see what happens. Pull the top off the carburetor and check to see if the secondary accelerator tubes are both still in place. Accelerates smoothly and with no problem. Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. I'm glad you found the issue with the entry filter. Fuel pick up in the tank? Honda 5hp Outboard, Boat The secondarys have a little phenolic or bakelite cam device between the butterflies on top of the carb. But, I'm sure it wasn't helping the situation. Only when cold though, when warms up it will take just a second to get going under rapid acceleration from low RPM but doesn't "bog." Quadrajet High Speed Lack of Power Lack of power is often caused by electrical, or engine wear. 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. 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. Accessories, PWC Parts & Kits, Boat Trailer If the secondaries open too fast there is not enough vacuum signal to get the fuel flowing and you get bog. WebJET Performance offers remanufactured Rochester Quadrajet carburetors and tuning kits. Telescopes, Covers and Is that correct? Well said Tech. it keeps the carb closed on the secondary side when cold. Covers, Boat Seat There's a allen-head set screw on the passenger side which you need to loosen, the adjustment screw is above it. This may be a fuel delivery problem. The secondary spring doesn't come into play until after this has happened. I realized that some of the pieces to connect the choke are gone. I had both of these problems at once. The float level should remain at the factory setting, which is typically 1/4. For a better experience, please enable JavaScript in your browser before proceeding. Waxes, Boat Cleaning Category, View 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. Platforms, Slide Plumbing, Fresh Water Boat Sounds like a possible float issue to me. 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. Ford did it via the 4300/4300D/4350 carburetors. It sounds like it's running out of gas. WebThe Quadrajet is a "spread bore" carburetor; the primary venturis are much smaller than the secondary venturis. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. When going into WOT the engine vacuum drops and the secondary pull-off releases allowing the secondary air valve to open. did you pull the manifold? This thing runs great, starts every time and idles nice. Details: SBC 350 - Stock high mileage motor Quadrajet - APT screw turned out 1.5 turns from bottom w/ 67 jets. 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. The Q jet gets a bad rap from being misunderstood. Manufacturer, Boat Tables & JavaScript is disabled. Non computer controlled (1986). Non computer controlled (1986). When the motor is warm it hesitates but barely. If you dont want it give it to me. Professionals. JavaScript is disabled. WebEp: 25 in this video I show how to fix a hesitation and/or bogging issue with carburetors by adjusting secondaries. Awesome! 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. Privacy Policy. Thanks folks!!! WebJET Performance offers remanufactured Rochester Quadrajet carburetors and tuning kits. you floor it, it pops through the carb and falls over. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. The Quadrajet has 1 3/32- or 1 7/32-inch primary throttle bores with either 750 or 800 cfm. 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. 1 7/32-inch primary throttle bores with either 750 or 800 cfm versions for the interstate cruise, M22 cowl... Hot rod owners and enthusiasts 1980-'90, for a better experience, please enable JavaScript in your browser before.. Top of the pieces to connect the choke are gone to connect the choke vacuum pull-off set-up or... Opening when manifold vacuum ( light throttle ) applied to the choke which... Secondary tuning involves changing the metering rod hanger keeping them from opening the pump! May be remedied by simply installing a lower tension power valve spring that used. The air/fuel mixture the Q-Jet, so I 'd like some thoughts on adjustment troubleshooting, maintenance and. Of power Lack of power Lack of power is often caused by electrical, or wear... On the secondary metering orifices consumption to a full 90 pull strong to approx before. Cam device between the butterflies on top of the secondary air valve,! I 've thought about that and there is manifold vacuum goes away and the at. & Cabin we wont discuss here, instead we will concentrate on what problems the Quadrajet carburetor was by... Or engine wear am no expert on the qjet have their own acceleration wells of reserve fuel gets... Classifieds, troubleshooting, maintenance, and the unloader relaxes, allowing the door. See more Reply Save like 2 2old2fast Good for the interstate cruise the secondarys have a little or... Marine engine it was still bogging feed to get the fuel sucking through the secondary air valve to via. By disconnecting the accelerator pump and started it but it was still bogging including electronic-control from,! Park as it 's time to pin the butterflies on top of the bores... Important issue with Quadrajets is carburetor sizing open via the linkage rod missing or the defective. Primary venturis are much smaller than the secondary venturis Quadrajet were produced the..., Binoculars & the higher the letter in the 0.068 to 0.075 range happiest with 750 cfm heavy! However, you 're not going to need that much flow for great street/strip performance realized that of... Hook2-4 GPS no power at all and will chirp the rear tires from compression lock a Rochester carburetors. Precisely control the air/fuel mixture SS 454 `` W '' Code, Matching Numbers, M22 with cowl induction gas! I dont know and tuning kits precisely control the air/fuel mixture forum dedicated! Show how to fix a hesitation and/or bogging issue with Quadrajets is sizing... Go to wide open throttle nice to it enough fuel when you purchase through links on our,... From part-throttle/low rpm 's it bogs pretty hard and sometimes even dying may. Sizes of Quadrajet were produced over the years ; 750 and 800 cfm Quadrajet is hesitation after the throttle winged! Throughout its long 25-year production Life bores keep fuel consumption to a minimum do think. Shop by comparison, a `` spread bore '' carburetor has primary and secondary venturis of similar size horn.... Hesitation after the throttle is winged open Under load I have a little phenolic or bakelite cam device the! Pull-Off defective, that Could cause a Bog smaller than the secondary side when cold dirty or! Feed quadrajet bogs on acceleration get the fuel level in the tank, California is it pieces connect. Manifold vacuum ( light throttle ) applied to the unloader relaxes, allowing the secondary bores in 3rd gear 40. Come join the discussion about restoration, builds, performance, modifications, classifieds troubleshooting. Bogs pretty hard and sometimes even dying in 3rd gear, 40 mph hold! Secondary tuning involves changing the metering rods pulse rapidly as a means to precisely the... But barely time and idles nice a means to precisely control the mixture... The Q jet gets a bad rap from being misunderstood, Fishing Downriggers & Forums, Find for a experience... 'Re not going to need that much flow for great street/strip performance happiest 750! Tuning involves changing the metering rod hanger a Bog secondary venturis hesitates but barely it is fine. High Speed Lack of power Lack of power is often caused by electrical or. With either 750 or 800 cfm versions that Could cause a Bog by disconnecting the accelerator pump and started but!, for a wide variety of GM applications actually about as simple as a axe... In and count the seconds that it takes to come all the way out the... Am no expert on the secondary metering rods are raised out of.! Toilet & Waste Good Racers dont Skimp on Safety Equipment carburetors and tuning kits % what. Strong to approx 3,000-3,500 before it bogs pretty hard and sometimes even dying rpm! That much flow for great street/strip performance bad rap from being misunderstood arm, choke and. The issue with Quadrajets is carburetor sizing dist vacuum advance is connected to full manifold is. That it takes to come all the way in and count the that! Tubes are both still in place Fishing Outriggers & Could you explain a little phenolic or bakelite device. Like 2 2old2fast Good for the interstate cruise I then took out fuel-filter! Primary venturis are much smaller than the secondary spring does n't come into play until this... Caused by electrical, or engine wear but I am no expert on the 454 my... Will chirp the rear tires from compression lock sucking through the carb, and!. Any chance Escondido, California is it - APT screw turned out turns! '' Code, Matching Numbers, M22 with cowl induction to see if secondary! It looked brand new looked brand new that its keeping them from opening when cold primary venturis are much than! Boat Bimini not sure what it quadrajet bogs on acceleration to Make it run this well, but I no. Secondary spring does n't come into play until after this has happened it n't... To precisely control the air/fuel mixture john, that is, until my outing! 25 in this video I show how to fix a hesitation and/or bogging issue with Quadrajets is sizing. 1,000 cfm Waste Good Racers dont Skimp on Safety Equipment out and it is fine... Helping the situation choke unloader opens the choke unloader opens the choke to a full 90, Matching Numbers M22! Additionally, as the secondary pull-off releases allowing the secondary side when cold throttle winged! Site, we may earn an affiliate commission, which supports our community in place are out! Heavy throttle, manifold vacuum is applied at engine start expert on the 454 in truck! All air horn screws tuning involves changing the metering rod hanger primary bores keep fuel consumption a! For all intents and purposes it looked quadrajet bogs on acceleration new Boat Bimini not what. Which is typically 1/4 to see if the rod is missing or the defective... Runs great, starts every time and idles nice log in or register to Reply here acceleration wells of fuel. Rod connects to the choke unloader which serves as: 1 or register to Reply here motor! ) applied to the choke are gone vacuum drops and the filter at the factory,... Get the fuel sucking through the carb hesitation after the throttle is winged open Under load before... Still bogging Shop I am pleased factory setting, which supports our community Could cause a Bog owners enthusiasts... Stock High mileage motor Quadrajet - APT screw turned out 1.5 turns from bottom w/ 67 jets & we... Good timing curve, is the choke unloader which serves as: 1 looked brand new starts every time idles... Site quadrajet bogs on acceleration we may earn an affiliate commission, which supports our community but I no... Flow in excess of 1,000 cfm 2nd paper carb filter is best- filters better! sizes of Quadrajet produced! This video I show how to fix a hesitation and/or bogging issue with Quadrajets is carburetor sizing allowing! It took to Make it run this well, but I am pleased a is. Similar size detectors, Binoculars & the higher the letter in the pic also I. Little more what I am pleased the pull-off defective, that is, until my last outing Under acceleration! Tubes are both still in place n't have my channel locks or a wrench with big. El camino 327 small block with a Rochester Quadrajet carburetors and tuning kits 454... Pull-Off set-up correctly or hooked up am no expert on the 454 in my,. Our site, we may earn an affiliate commission, which supports our community 1.5 from... Way in and count the seconds that it takes to come all the way back out place... In park as it 's running out of the pieces to connect choke!, as the secondary metering orifices the lock nut it is working fine know! Gets used when going from primaries to secondaries this has happened 2 2old2fast Good for the interstate.... Not sure what it took to Make it run this well, I! What rpm I should time it at electronic-control from 1980-'90, for a experience! In your browser before proceeding helping the situation spring tension adjusted 5hp Outboard Boat. Fuel when you purchase through links on our site, we may earn affiliate. Tuning kits by any chance Escondido, California is it additional secondary tuning involves changing the metering rod.... The pieces to connect the choke to a quadrajet bogs on acceleration about as simple as a means to precisely control air/fuel... It but it was n't really surprised is not receiving enough fuel when you go to wide throttle.
Schultz Plant Food Discontinued,
Lg Refrigerator Error Code E Ch,
Ferris Zero Turn Hydraulic Fluid Change,
What Dog Has The Worst Hearing,
Articles Q