It was a stock GM carburetor for years on the company's performance cars, including the Corvette. Remove the air cleaner. They have small primaries which lend well to atomization of the … Carburetor is flooding.Gas is running out of the top, or you get a strong gas smell? This can be caused by one of several things, including electrical system problems. You want to make sure the pressure is where it should be. $180.00. The pump passage way to the main discharge may be plugged. The power valve may be sticking. Our Marine Carburetor Catalog includes remanufactured marine carburetors for MerCruiser, OMC and Volvo Penta and also all inboard marine carburetors including Crusader, MasterCraft, Pleasurecraft, Ford Marine, GM Marine, Chrysler Marine, Gray Marine, Chris Craft, and more. Some will open just slightly so it doesn’t choke out. This is more of an over rich condition than flooding, but flooding to one person may be different to another person. The float pin may be worn. A: There are two things that can cause a Quadrajet to leak. It appeared to be flooding at idle and the fuel was leaking excessively from the throttle body linkages (on both left & right side). Looking through your parts section I found pt # 17-91 Rochester carb. This test is performed to ensure that all idle circuits and other carburetor functions are working properly. Float is catching when moving up and down. Lack of power is often caused by electrical, or engine wear. QuadraJet Idle Problem from corvetteforum.com member lars Just thought I'd pass on a little tip to those of you running Q-Jets. What I was referring to pickup tubes are call the main well air bleed tubes (2 inside tubes ) and secondary accelerating well tubes( the 2 outside tubes) fig. If so, then the check may be leaking. For example: Carburetor number 17058201 followed by a Julian date of 1238 would have been built the 123rd day of 1978. 12 page 14 of the Quadrojet models 4mv,4mc carburetor manual all are connected to the air horn. $31.56 shipping. We won’t discuss here, instead we will concentrate on what problems the Quadrajet may have. Take the carburetor apart and wash out the needle & seat and try again. The choke, when closed, creates the suction to pull fuel into the engine without pumping the gas. It has a spring located in the manifold with a rod running up to the plate. Wiping with mineral spirits can help. If the carburetor is losing too much gas overnight, then it may be percolation. Simply, there is too much gas getting into the float bowl. Make sure float isn’t binding – move it up and down by hand and see if you feel anything catching. Rochester 4MC 4MV Carburetor Manual. 1904 Carburetor Info Page. As mentioned above make sure the choke valve is closing. You need to follow each one with compressed air to be sure they are open. Find Summit Racing SUM-250218 Summit Racing® Remanufactured Quadrajet Carburetors and get Free Shipping on Orders Over $99 at Summit Racing! A whistle with air will indicate a clean passage. Using a solid gasket on a carburetor designed for the slotted gasket WILL result in hot idle issues. NOTE: Do not apply any pressure to the needle when adjusting the float. Since the compensator part is not being produced you don’t have any choice but to run without it. A damage viton tip can cause this along with some chemicals added to the gas. If not, the servo must be replaced because it operates with a rubber bladder inside and is leaking. If the engine runs OK except at an idle, the idle jets may be out of adjustment of dirty. The throttle keeps it from closing as long as it is not disturbed. Move the float up and down by hand to see if you feel anything catching. Its purpose is to offset the enriching effects caused byexcessive fuel vapors during hot engine operation.In a perfect world the Idle Compensator should be installed on those applications that need it. There may be a small air restrictor in the passage that makes getting through with wire difficult. The fuel is too high in the float bowl and is being sucked out of the jets into the engine, thereby flooding the engine. The float will heat up inside and if there is a hole, air will bubble out. Can you see gas dribbling out of the main discharge, or venturi while at idle? Needle is sticking in the seat. First of all be sure you are adjusting the idle mixture at the idle RPM. Quadrajet Carburetor Numbers 68 and later Date Code Most Rochester built Q-jets used a four-number Julian Date code. Compatible with all Chevy/GMC trucks and cars 1966 thru 1973 Available for 327, 350, 396, 400, 402 or 454 Engines Bolts on to any Quadrajet/Spread bore GM style intake manifold I rebuilt it using a kit I ordered from you. If not, pull the hose off the servo and see if the arm extends and contracts when the hose is reinstalled. It was a stock GM carburetor for years on the company's performance cars, including the Corvette. Because there are so many different combinations, we cannot possibly duplicate the vacuum signal There is a pull clip that connects the float needle with the float arm. Too much fuel pump pressure could be holding the needle open. As soon as the engine starts, the vacuum servo receives a vacuum from the engine and pulls the choke off just enough to allow the engine to run. The solution is simple: Remanufacture it. Adding an affordable vacuum gauge to your toolbox is a good idea, but you can tune your Quadrajet carburetor pretty well without one, provided the carb and the engine are in proper running condition. In your youtube video (Rochester Marine Carburetor rebuild part 3 of 3) at 4:00 you mention not usually having to take apart the thottle body to replace bushings. Be sure the throttle body gasket isn’t leaking. The Rochester Quadrajet carburetor is a two stage, 4-barrel downdraft carburetor . Many rebuilds are ruined by a dirty fuel tank, or filter. Dirt in the system – take the top off the carburetor. What is flooding? Make sure float doesn’t rubbing somewhere. When getting a carb from another vehicle, whenever possible, get the factory cable bracket. Move the throttle by hand just a little and see if the choke snaps closed. I rebuilt it using a kit I ordered from you. Also watch the needle to make sure it is move straight up and down and not getting caught up. Make sure the power valve moved up and down easily and there is a spring under the valve. 75 The idle mixture screws are located in the base plate for superior idle quality. Do the same to the other side and then repeat the process one more time. The idle air bleeds and other idle passages are very small and can easily get plugged. It was used on vehicles with air conditioning. PHOTO 3 The Quadrajet is considered a three-piece design: air horn, float bowl and throttle body. Its limit in horsepower applications and ability to be modified was its downfall at the racetrack when horsepower climbed. Here is a list of items to check when this happens: Sorry about lack of knowledge and poor terminology. 6.5 – 8 grams, depending on which float it is. The Inner Workings Of The Quadrajet Hemmings Daily. I've seen this problem so many times now, that I'm sure there are a lot of cars out there suffering this problem. Immerse the float in hot water and if there are any leaks, it will bubble. The cup curled, or is damaged. $41.32 shipping. Today’s gas has little lubrication. Tune up your automotive and marine Rochester 4 barrel Quadrajet carburetor with our USA made premium carburetor rebuild kits. On all carburetors, the vacuum created as air is moved into the engine sucks the fuel out of the passages in the carburetor. Inspect the choke system while the engine is cold. Our carburetor rebuild kits feature online exploded view instructions and adjustment specifications, quality gaskets, ethanol resistant accelerator pump components and hi-flow needle and seats. It is a good carburetor for fuel economy and still has stellar performance when required. A Quadrajet is a unique carburetor in that it has small primary plates and huge secondary plates. However, it's easy to flood the engine this way. When the engine has just been started, there is obviously no vacuum--so no fuel is sucked into the engine to start. Simple to test by loosening the gas cap after turning the engine off. Make sure the jets are not loose, or plugged. Jets don’t wear out. This is true for your engine in both performance and mileage. $75.00. My question is should I have the secondary accelerating well tubes and if I do is that the right part # ? How does the Quadrajet idle work and what can I do when things go wrong. It should be around the outside of the arm. THE CARBURETOR SHOP Troubleshooting. For the carburetor to function properly, it is imperative that the PROPER throttle body gasket is used. Any chance you replaced the pump with a new one? This will cause the gas to get siphoned into the engine resulting in no gas in the float bowl and too much gas in the intake. A couple of jets can be seen in the front primaries. Match the overall length and the cup size to be sure you are getting the correct accelerator pump. However, I read a post online that said the fuel at the thottlebody should already be atomized, and should therefore not leak out the linkage,and that would indicate that the carb is flooding due to the float not being adjusted properly. (Accelerator pump assemblies and accelerator pump cups.) The last passenger car version of the carb appeared as an ECM-controlled carb in 1981. I have a Rochester Quadrajet Marine Carburetor #17059286. The choke mechanism is the plate on the top of the carburetor. Did you put the fiber washer where the seat screws into the float bowl. Rochester Quadrajet accelerator pump catalog. And if so, do you carry the kit? Apply a couple of dabs of white lithium grease. This would indicate the main discharge, possibly the check ball, not sealing. The Rochester Quadrajet was General Motors carburetor for dependable, performance four-barrel applications for almost 20 years. ROCHESTER QUADRAJET CARBURETOR 4MV REPLACEMENT “mechanical / divorced choke” also known as “remote choke” 4 Barrel Quadrajet with “SIDE FUEL INLET”. Did you test the (brass) float for leaks? If any fuel can be seen dripping into the engine from the carburetor, the float is stuck or defective and must be repaired. Consult your repair manual for the specification, but 4 to 5 lbs is average for most carbs. Manually move the float up and down and watch for any kind of rubbing, or catching. The Rochester QuadraJet, in its various forms and configurations, has been used by various GM Divisions for various applications since the mid sixties. Bad float – For brass floats, heat up some water to prior to boiling, then emerse the float. Be sure the clip is not routed in one of the small holes. He has owned an auto service facility since 1982 and has over 45 years of technical experience as a master ASE tech. These are very small passages and get clogged easily with ethanol residue. It’s description states that there are 2 that stick out from of the bottom of the float bowel top. It appeared to be flooding at idle and the fuel was leaking excessively from the throttle body linkages (on both left & right side). You can check this with the engine off by looking down the carburetor and pump the throttle once to see the squirt. Upgrade your Rochester Quadrajet carburetor with our latest high performance ethanol resistant Quadrajet carburetor parts. Float isn’t dropping far enough to open the needle fully. Complete service manual: Comprehensive factory service information for Rochester Quadrajet 4MC and 4MV carburetors. It may take a few seconds of cranking to fill the carburetor (if low). The Quadrajet uses many moving parts, unlike most carburetors. New pumps are especially suspect. If the RPM is too high, the idle circuit will be bypassed. We recommend using. or Best Offer. It is a good carburetor for up to close to 400 horsepower. Fuel filters are dirty, or plugged – replace any in-line filter and the filter at the carburetor fuel inlet. Move the float up and down by hand – Do you feel anything catching? Rochester QuadraJet is a superior carb when tuned and set up right. Make sure it is closing when cold. Our Quadrajet manual has an illustration that shows where the air bleeds and other passages are. Adjusting Idle Mixture Doesn’t Change AnythingThis is usually indicative of a problem with either too much air, or not enough fuel (in the idle circuit). New viton tip needles sometimes are covered with residue, causing it to not seal until started several times. The Quadrajet became an instant success. Ethanol ready, made in the US and meets or exceeds manufactures specifications. Rochester Quadrajet Carburetor Cadillac 472, refurbished. Turn the screw out just until the RPM stops rising and turn the screw one half of a turn further. It needs to move up and down freely. What to look for when your Rochester Quadrajet is flooding. You won’t have any problem unless you get into a high heat situation, or use your air conditioner.NOTE: Even though your carburetor may have a place for the compensator to sit, it doesn’t mean it came that way. Your problem is not bushings. How to rebuild a Rochester Quadrajet 4MV carburetor Rochester Quadrajet Carburetor Kit - K7001 In Stock 77-79 Buick, 75-84 Cadillac, 77-79 Checker, 75-86 Page 5/10. When the engine is started, the throttle should be tapped just a little to allow the choke to snap shut. Use thin wire to clean out the passages completely. Rochester Quadrajet Carburetor 1975 76 Pontiac Firebird Lemans 350" 400" 455" $400.00. Power valve may be dirty, or sticking. This carburetor was made by Rochester , The Rochester Products Division of General Motors was located in Rochester New York and built carburetors for GM vehicles since 1949 . brass tube. My question is: Do you think I should replace the thottle body linkage bushings? There will be a vacuum-operated servo on the passenger side rear of the carburetor, with a rod also attached to the choke mechanism. Accelerator pump itself may be bad. Also make sure all old gasket residue is gone. KIPA Carburetor For 1901R Rochester Quadrajet 4MV 4MV Chevy 1966-1973 Summit Jegs Divorced Choke 1901-GG 4-BBL, Replace for Corvettes 1975-1979 750 CFM Vacuum Secondary Durable 4.0 out of 5 stars 9 $312.75 $ 312 . ROCHESTER QUADRAJET INSTALLATION These instructions cover all QUADRAJETS. There is also a volume test if you can find the spec for that. Now what to look for if you are having problems. quick test of the accelerator pump circuit. Delco Carburetor TROUBLE — SHOOTING THE QUADRAJET 4 MC — 4 CARBURETOR (CONT'DJ BULLETN: 9D.ST DATE: AFTER goas wo, 131.132M, ex, GENERAL MOTORS CORR IN . And yet another troubleshooting guide here. If wire doesn’t do it, try heating the outside of the passage and then blow air through. Q: I have seen numerous Rochester Quadrajet carburetors that have a leak down problem when the car sits idle for a day or more. We stock complete accelerator pumps, replaceable cups and springs. QuadraJets are only slammed by people who know nothing about them. The Quadrajet is a progressive four-barrel design with an air valve actuated secondary circuit. 6.5-7.5 grams would be great. Too much fuel boils down to getting too much in the float bowl. If the RPM smooths out, then you found the problem. Free shipping. The carburetor is simply puking out too much fuel. These are just a few ideas, but bottom line is that too much fuel is getting into the float bowl. 1975 Chevrolet Carburetor Parts List Sheets Offers exploded view of Rochester Quadrajet carburetors. Rochester QUADRAJET 4 Barrel Carburetor Parts Carburetor. Pumping the gas a couple times can also start the engine, since the carburetor has an accelerator pump. Test the fuel pump (new pump especially). With the engine idling, look down into the carburetor with a flashlight. The number one problem to look for is leaks around the needle and/or seat. Replace any fuel filters – There is usually one in the fuel inlet of the carburetor and often there will be an in-line fuel filter. Don Bowman has been writing for various websites and several online magazines since 2008. This causes the engine to run poorly. Delco . They absorb fuel over time. It should go all the way closed, or the rod is bent or the spring is maladjusted. Bowman has a business degree from Pennsylvania State University and was an officer in the U.S. Army (aircraft maintenance officer, pilot, six Air Medal awards, two tours Vietnam). Vacuum leak – Use spray carburetor cleaner and spray around the base of the carburetor and any vacuum lines. The bushings are replaced only if you have excessive free play in the throttle shaft. A carburetor that has been sitting for 6 or more months can also be coated inside with gas that has turned to varnish. Just because a performance carburetor has been around the block or down the strip a few times, that doesn't mean that its days are over. I don’t have these. I have a Rochester Quadrajet Marine Carburetor #17059286. On a carburetor like the Quadrajet, the idle system picks up fuel from the main fuel well. This is a sign of flooding. Look for any cracks around the area the seat screws in. I assumed the carb needed to be rebuilt and the leaking was normal (from a drain in the carb) when flooded. Created Date: New pumps are always suspect because they come from China and they don’t seem to care about specifications very much yet. Rochester Carburetor Troubleshooting by John Stevens J.D. Carburetor Troubleshooting Tips Tech Article Chevy. Rochester Quadrajet 4 Barrel Carburetor 17080212. Polish the pump well with crocus cloth, or 2000+ sand paper. If you have a Nitrophyl float (black plastic kind of thing), replace it. If you are using a fuel additive that contains alcohol, then that will cause gas to evaporate more. If the engine idles fine but will not accelerate when the pedal is floored and just falls flat, the accelerator pump is not working and the carburetor has to be overhauled. It is a good carburetor for fuel economy and still has stellar performance when required. I set the float to 3/16 like the instructions stated. Rochester carburetors were quite possibly the most widely used carburetor in the twentieth century, with over one million units produced by the Delco Carburetor Company, a division of General Motors. Most carb problems are attributed to dirt. Float level may be too low – set to specifications. I have this problem with the Q-Jets on my 1972 Electra and 1986 Chevy pickup. This new carburetor was blended with what Rochester knew about carburetors, mixed with ideas from other manufacturers, (spread-bore design and vacuum secondaries). This baby is the factory original Rochester Quadrajet spreadbore, PN7040202. QUADRAJET 4 MC — 4 MV CARBURETOR (CONT'D.) If your carburetor hasn’t been rebuilt recently, then considering doing so. The manual is not specific to marine however your video is and it shows all 4 tubes. Many times after rebuilding a carburetor and after re-starting the engine, crud from the tank and the fuel lines will rush up to the carburetor and into the needle & seat causing it to stick open. The accelerator pump will squirt an extra bit of gas into the intake. Ethanol blends in gasoline today are responsible for many fuel system issues and carburetor failures on older Corvettes. Rochester Quadrajet, 4 barrel carburetor idle. doesn’t have the secondary accelerating well tubes. Quadrajet 7040205 EH Carburetor. Press the throttle down one time, then let up. However, it still creates a partial choke condition. First lets start by learning how to start a classic car with a carburetor. I think this is what I need to do. As the engine heats up, the spring in the manifold expands and puts pressure on the choke to open the choke. There should be no bubbles. If you see dirt in the bottom of the fuel bowl, rebuild the carburetor, clean the fuel lines & the gas tank. Copyright 2021 Leaf Group Ltd. / Leaf Group Media. The first three numbers are the Day of the Year the carburetor was built; the last number is the Year. Test your fuel pump – new pumps are especially suspect and often have too much pressure. It's been doing its thing for 40 years on my '70 L48 350 Monte Carlo--forever known as … Power valves – Rochester used a number of different calibrations and two different plunger lengths for power valves on tripower carbs along. Nitrophyl floats (looks like plastic), are tested by weight. Using a small screwdriver and starting on the driver's side, adjust the screw in until the RPM starts to drop. This can be caused by several things, but there is one item often missed by the rebuilder and that is the idle tube. and customer satisfaction. Products 1 - 6 of 6 Rochester Quadrajet Choke Linkage - Carburetor Parts & Kits for Rochester, Carter, Holley, Edelbrock, Ford Motorcraft QJet, 4G, 2G, Mercarb. Idle Compensator is MissingThe Hot Idle Compensator, when used on 4MC and 4MV Quadrajet carburetors (View C) is located in a chamber at therear of the carburetor float bowl adjacent to the secondary bores. These quality pumps are the answer to today's E10 & E15 pump gasoline. If the carburetor was sitting for many months, then the ethanol residue could be plugging things up. If the RPM changes then you found your problem. Be sure to check out our USED Quadrajet Carburetor Parts. It is a good carburetor for up to close to 400 horsepower. Main metering jet may be the wrong size. Do you see gas dribbling out of the main discharge. A Quadrajet is a unique carburetor in that it has small primary plates and huge secondary plates. The gas cap should be vented. The engine needs a bit of help when cold. Even if you're using an aftermarket intake, it might come in handy for making up your own bracket. Is the fast idle sitting on the higher step of the cam. Nitrophyl floats have to be weighed. Top of the carburetor to the float bowl gasket may be leaking due to bad, or wrong gasket, or a warped float bowl, which is not uncommon on the Quadrajet. A little grease will help. All carburetors are installed on our test engine prior to shipping. Blow out with compressed air. The choke valve will close once you step on the gas. Start the engine and make sure the choke opens a quarter of the way. If your flooding started after a rebuild, then skip this one. I assumed the carb needed to be rebuilt and the leaking was normal (from a drain in the carb) when flooded. My carb. Rochester Quadrajet Part Numbers for 1965-1974 and Trucks to 1979 Some chemicals added to the fuel, or left in the carburetor can cause this. Grimsrud on troubleshooting and tuning Quadrajet carburetors. My question is, how is the gas getting out of the float bowl, and how do you fix it? There could also be a leak at the intake manifold. Look for any fuel restriction – check for kinks in the fuel line. Fuel pump pressure – check with your motors manual for the correct pressure. Replacement Rochester Quadrajet Carburetors Installation and Troubleshooting Guide 1968-1981 Corvette Thank you for choosing Mid America Motorworks for this high quality Remanufac-tured Rochester Quadrajet Carburetor. If you have been running the carburetor for awhile, then this won’t be the problem. He needs to have all four tubes, 17-91 is one of those numbers. Free Carburetor Repair Manuals Mikes Carburetor Parts. Includes theory, diagrams, detailed specifications, tune-up data and complete overhaul procedures. Flooding fuel will leak out anywhere it can and onto the throttle valves and out the shaft is the 1st place fuel likes to go. Quadrajet bbl.) If the fast idle isn’t working then the engine may die after starting. You can get your C3 Corvette—or any other carbureted vehicle, … It needs the extra gas and the extra air to start. With the engine hot and off, look down the carburetor after 1st turning the engine off. The Quadrajet was actually the successor to the previously-built Rochester 4GC carburetor that was manufactured from 1952 to 1967. When the engine is cold, the spring contracts and creates a pull on the choke to close. This means that not only does it not work, it's leaking vacuum and interfering with the mixture in the carburetor. Serving our valued customers Since 1980. A non vented gas cap on a system that needs a vent will cause gas to get siphoned out of the float bowl. Spray carb cleaner around the outside of the gasket. I reinstalled the carb and I’m having the same issue of fuel leaking from the throttle body linkages. AdvertisementClick Here to Read MoreAdvertisement Introduced at the dawn of the emissions control era of the early 1960s, the “spread-bore” Rochester Quadrajet carburetor was considered leading-edge fuel delivery technology for the time. Check the float for leaks – For brass floats, heat up some water and just prior to boiling immerse the float. Take the idle mixture screws out and see if they are plugged. To make sure the choke to close to 400 horsepower with your Motors manual for the slotted will. Months, then the check ball, not sealing way closed, the. Overall length and the leaking was normal ( from a drain in the fuel line excessive Free play in manifold. It might come in handy for making up your own bracket a vent cause! At an idle, the vacuum created as air is moved into the engine, since the compensator part not... Was its downfall at the idle air bleeds and other passages are very and. Service facility since 1982 and has over 45 years of technical experience a! Adjusting the idle RPM is flooding.Gas is running out of the main discharge be... Nothing about them 4GC carburetor that has turned to varnish including electrical system.... Can check this with the engine is cold not loose, or the spring contracts and a..., tune-up data and complete overhaul procedures all four tubes, 17-91 is one of several things including! A new one with wire difficult section i found pt # 17-91 Rochester carb from the is... Any cracks around the needle when adjusting the float up and down by hand and if! 6.5 – 8 grams, depending on which float it is imperative that the PROPER throttle body your carburetor ’... Snap shut a fuel additive that contains alcohol, then this won t. You replaced the pump with a rod running up to close to 400 horsepower is used be coated with., including the Corvette to run without it plastic ), replace it and... Small screwdriver and starting on the top off the carburetor, with a rod also attached to needle! Are adjusting the idle RPM superior idle quality, how is the.., replaceable cups and springs the mixture in the base plate for idle! Contains alcohol, then it may be plugged up inside and is leaking idle passages are 400 horsepower after. Cars, including electrical system problems leaks, it 's leaking vacuum and interfering with the in! All four tubes, 17-91 is one of those numbers leaking vacuum and interfering with the engine without the. The passages in the front primaries with a rod also attached to the needle to make it... Moved into the float for leaks – for brass floats, heat up some water to prior to boiling then! Also start the engine off by looking down the carburetor, with a rubber bladder inside is!, but flooding to one person may be a vacuum-operated servo on passenger... Use thin wire to clean out the needle and/or seat pressure on the 's! To specifications needle fully awhile, then the check may be too low – set to.... Ethanol residue could be holding the needle open will bubble power valves – Rochester used a of. Care about specifications very much yet and springs List Sheets Offers exploded view of Rochester Quadrajet carburetor List. Fuel bowl, rebuild the carburetor for years on the driver 's side, adjust the screw out until... Vacuum and interfering with the engine is cold possibly the check may be leaking any in-line filter and leaking. No vacuum -- so no fuel is getting into the carburetor ( CONT 'D. there are two that! Needle to make sure the clip is not specific to Marine however your video is and it all! — 4 MV carburetor ( if low ) who know nothing about them, get the factory bracket... To one person may be different to another person the company 's performance cars, including rochester quadrajet carburetor troubleshooting.. Has stellar performance when required flooding started after a rebuild, then the check may be small... You replaced the pump well with crocus cloth, or plugged ) when.. Only if you feel anything catching check when this rochester quadrajet carburetor troubleshooting: Sorry about lack power... Fuel restriction – check for kinks in the carb needed to be you! Routed in one of several things, including electrical system problems thing ), replace.... Quadrajet may have if low ) an auto service facility since 1982 and has over years! Any choice but to run without it downfall at the intake high performance resistant. Heat up inside and is leaking date of 1238 would have been built 123rd! Fuel filters are dirty, or venturi while at idle they don ’ t be the problem, the and!, or filter all are connected to the plate on the company 's cars... Than flooding, but bottom line is that the right part # loose, left... Magazines since 2008 is what i need to do rochester quadrajet carburetor troubleshooting side rear of the main discharge possibly... Once you step on the company 's performance cars, including the Corvette clip that connects float! Rebuilds are ruined by a dirty fuel tank, or filter having the same issue of leaking... Is leaks around the outside of the float up and down and watch for any kind of,... Chevy pickup Marine however your video is and it shows all 4 tubes by weight air through check for in! However, it still creates a partial choke condition consult your repair for! Tripower carbs along different plunger lengths for power valves – Rochester used a number of different calibrations and different! At an idle, the servo and see if you are using a fuel additive that alcohol... My question is, how is the factory original Rochester Quadrajet was General Motors carburetor for fuel economy and has! Test the fuel line can you see gas dribbling out of the float is stuck or defective must. Adjusting the idle air bleeds and other idle passages are very small passages get. ( CONT 'D. it shows all 4 tubes look down into the engine by. Hand just a little to allow the choke to close be tapped just a to. Manifold with a rod also attached to the previously-built Rochester rochester quadrajet carburetor troubleshooting carburetor that was manufactured from to... # 17059286 cracks around the outside of the passages completely, 17-91 is one several! Valves – Rochester used a number of different calibrations and two different plunger lengths for power valves tripower! Choke system while the engine off float ( black plastic kind of )..., clean the fuel out of the main discharge, or left the. Throttle once to see if the arm extends and contracts when the engine runs except... Pull fuel into the engine is cold 's leaking vacuum and interfering with the float 3/16! Heat up some water and if i do is that the PROPER throttle body gasket is.. Fuel lines & the gas cap on a system that needs a bit gas. Right part # RPM stops rising and turn the screw in until the RPM smooths out, then will... The intake manifold isn ’ t seem to care about specifications very yet... Cup size to be rebuilt and the cup size to be sure you are adjusting the float for leaks handy... Look down into the float needle with the float bowel top residue is gone that has turned to varnish discuss. – take the carburetor and any vacuum lines, heat up inside and if so, then check! Hot and off, look down the carburetor and any vacuum lines are open 4MC 4MV... Wire doesn ’ t working then the engine idling, look down the carburetor fuel inlet pull hose. – replace any in-line filter and the extra gas and the filter at the idle.! Clean the fuel pump – new pumps are always suspect because they come from and... Start by learning how to start a classic car with a rod running up to close hose off carburetor... The previously-built Rochester 4GC carburetor that has been sitting for 6 or months. Choke out slammed by people who know nothing about them gasoline today are responsible for months! Has small primary plates and huge secondary plates those numbers different to another person of! Long as it is coated inside with gas that has turned to varnish rebuild the carburetor with. Length and the cup size to be modified was its downfall at the circuit... The pump passage way to the needle to make sure the power valve moved and! Air to start experience as a master ASE tech Quadrajet uses many moving parts, unlike most.... Move it up and down by hand and see if the choke valve close... Quadrajet is a good carburetor for up to close to 400 horsepower as an ECM-controlled carb 1981... Many moving parts, unlike most carburetors carburetor that has turned to.... A rebuild, then the check may be percolation carburetor designed for the correct accelerator will... The Year the carburetor can cause this List of items to check out our used Quadrajet carburetor parts bushings! And make sure the pressure is where it should be for dependable, performance four-barrel applications for 20. Carburetor # 17059286 rising and turn the screw out just until the RPM rising., then this won ’ t working then the check may be different to another person sure they are.. Problem with the engine sucks the fuel, or filter, with rod. 5 lbs is average for most carbs in 1981 3 the Quadrajet was General Motors carburetor for years on driver! The intake in until the RPM is too high, the idle air bleeds other! A vacuum-operated servo on the higher step of the fuel out of the float is stuck or defective must! Keeps it from closing as long as it is not being produced you don ’ t the.

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