Dock, Cabin and Most modern Copyright 2019 IBOATS. JavaScript is disabled. By comparison, a "square bore" carburetor has primary and secondary venturis of similar size. That's the best all around deal. I don't think your problem is the carburator. 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. That check valve being coroded up badly was the main culprit!1 The paper filter -likely was catching the crap from that corosion!! It may not display this or other websites correctly. Charts & Zincs, Generator Parts, Boat Tubing & Bullet Skimmer, Paint and If the secondaries open too fast there is not enough vacuum signal to get the fuel flowing and you get bog. The boat is going out early Saturday morning, so if it was just the valve and all works, then sweet. Biminis, RV & Trailer Locks, Boat Deck 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. Terminal Good Racers Dont Skimp on Safety Equipment. you floor it, it pops through the carb and falls over. Another possibility, and it is real. 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. Engine is 1986 model mercruiser MIE 340 big block with quadrajet carb. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. It may not display this or other websites correctly. http://forums.highperformancepontiantiac/quadrajet-secondary-accelerating-wells/. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. Screws, Boat Handles, Pulls, As the fuel enters the carburetor, it must pass through the inlet valve, often referred to as the needle and seat assembly. The accelerator pump may be replaced with a high-performance type (EDE1982) to give more pump shot, when desired. 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. I started up and checked for leaks everywhere before i left, and i noticed as weird as it sounds, my idle was lower. and it seemed like i was running rich. Big-blocks want 800 cfm. That 2nd paper carb filter is best- filters better!! You must log in or register to reply here. Could this work just as well in place of the choke rod? thanks NH! I wouldn't sweat that idle speed change. Trailer Winches, Shop I put in the new valve and double clamped the fuel line to the barb (which was the same size as the old one, but the barb was longer. Systems, Lowrance Hook2-4 GPS Pull the top off the carburetor and check to see if the secondary accelerator tubes are both still in place. Primary jet size is commonly in the 0.068 to 0.075 range. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. I don't think it's too much that the engine vacuum at WOT would keep it from opening. Tackle Boxes, Fishing Bait & During recent runs, engine bogs at 2500 rpm (normal WOT is about 4000), starts to choke a little. 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. There is no mistaking that quadrajet sound when you get into it, so I don't think that its keeping them from opening. A damper to slow down the opening rate of the air valve to approx 1 to 3 seconds. Discussion in 'The Hokey Ass Message Board' started by socal_wrench, Dec 24, 2005. Deals, Electrical That also could have contributed to the problem yet was doing its job!! Thanks you guys im going to be working on the elky in a while ill check it out. I'm glad you found the issue with the entry filter. My 89 5.7 qjet changed idle quite a bit. We wont discuss here, instead we will concentrate on what problems the Quadrajet may have. It controls the air door, if the air door opens too quickly it will hesitate. 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. it keeps the carb closed on the secondary side when cold. Fuel metering became electronically controlled in 1980. I have a quadrajet on the 454 in my truck, electric choke etc. The 800 CFM unit (identified by a slightly larger primary venturi) was relatively rare, found only on 1971-73 Buicks and 1973 Pontiacs. The float assembly is removed next. To this day, many record-holding Super Stock cars run well into the nine second zone with Q-Jets atop their manifolds. Daytona Beach, FL. A damper to slow down the opening rate of the air valve to approx 1 to 3 seconds. Shelters, Boat When the motor is warm it hesitates but barely. Ventilation, Interior & Cabin A forum community dedicated to custom off-road vehicle owners and enthusiasts. 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. But damned if i didn't have my channel locks or a wrench with me big enough to hold the lock nut. The stock air valve spring setting is usually 1/2 to 3/4 turn from loose. did you pull the manifold? That would make sense when cold. 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). & Dock, Anchor Chains & Details: SBC 350 - Stock high mileage motor Quadrajet - APT screw turned out 1.5 turns from bottom w/ 67 jets. I don't know if its a problem but 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. The Quadrajet has 1 3/32- or 1 7/32-inch primary throttle bores with either 750 or 800 cfm. So whether or not that was causing my issue or not, i dont know. 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. This, of course, also depends upon the aggressiveness of your small-block. Forums, Find Communication, Auto Pilot The Q jet is a fantastic carb. Is it a good stream like you'd piss after drinking 3 PBR's? 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. Additionally, as the secondary air valve opens, the secondary metering rods are raised out of the secondary metering orifices. The check valve side wasn't bad. Boat Gel Coat - Spectrum Color, Pumps and Marine Battery Chargers, Shop 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. Accessories, PWC Parts & 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. What's more, the Quadrajet carburetor was employed by every single GM division throughout its long 25-year production life. You guys are always helpful here - and I'm kind of stumped on an issue with the Quadrajet and my engine. Any vacuum leak anywhere will cause driveability issues. 02. WebEp: 25 in this video I show how to fix a hesitation and/or bogging issue with carburetors by adjusting secondaries. JavaScript is disabled. 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. Hopefully it did something. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 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. Tops, Bimini Top Also check the choke pull off diaphram and vacuum advance can for leaks. Dollies, SportsStuff Great Big Keeps the air valve closed when there is manifold vacuum (light throttle) applied to the unloader. Ok I pushed the vaccum release all the way in and it takes 3 seconds for it to return. Riptide Terrova 80 Trolling Motor w/i-Pilot & Bluetooth, Inflatable Marble, Engine The secondary air valves, located in the air horn, allow a smooth transition into the secondaries via manifold vacuum at wide-open throttle. The secondaries on the qjet have their own acceleration wells of reserve fuel that gets used when going from primaries to secondaries. Lights, Boat Trailer A misadjusted secondary air valve spring can cause bogging but that's really only when you floor it. I rebuilt the Quadrajet and the car starts and runs very smooth. JavaScript is disabled. Needle sticking or not opening enough? Too many of us give up because this carburetor requires time, knowledge and patience. Hitches, & Authentication and pre-purchase inspection service still available. 1160 hours on engine. Ropes, Boat 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. 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. Insurance, Boat I don't know if its a problem but I have to tap the gas to get it to idle down after it starts. High Back Reclining Helm Seat, Cabin and That is, until my last outing Under heavy acceleration, the engine bogged down and stumbled. Galley, Covers and Another possibility, and it is real. Two basic sizes of Quadrajet were produced over the years; 750 and 800 CFM versions. Another method of rectifying this is by drilling a small hole in each primary throttle blade to lean the engine a bit at idle. PM me for more information. All, Boat Bimini Acessories, Fishing Outriggers & It needs to be loosened, and the air door spring tension adjusted. Timed to ~6 BTDC with vacuum advance disconnected.HEI distributor Elevation is 9,000ft. BUT even if the air valve is completely loose it won't cause a bog till the secondary butterflies are opened at the "tip in" point. 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. Along with a good timing curve, is the choke vacuum pull-off set-up correctly or hooked up. I put it at ~12 BTDC @ 800 RPM's. Check eBay, Craigslist and Racing Junk websites for options. That was in park as it's an automatic(th350.). Be sure your float level and fuel pressure is correct.If you have allready rebuilt it ,that may be the trouble. I rebuilt the 4-bbl Quadrajet in 2013 and haven't had any issues since.
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