rochester quadrajet carburetor troubleshooting

Put the pump in the well and push it down toward the bottom of the well. Teflon (either tape or paste) on a tapered fuel fitting. The larger check ball in the main discharge tube must also be tested. Engine sags, die outs and pop back during warm up are usually caused by retarded ignition timing, improper carburetor choke vacuum kick adjustment, cam index setting, fast idle speed, and mixture setting. There are typically two screws, one for each side of the carburetor. Ensure that compression is up to par in all of the cylinders, the valves are adjusted to their set clearances and the ignition system is operating properly. is probably the culprit. compensation devices HOT Take the carburetor apart and wash out the needle & seat and try again. I have a Rochester Quadrajet Marine Carburetor #17059286. simply research the suggested maximum cranking values for your engine. The number one problem to look for is leaks around the needle and/or seat. Rochester Quadrajet List by Carb Number - Kits, Floats and Parts Visual Guide to Selecting Quadrajet Rebuild Kits; manuals. The small holes in the venturi can be blocked with ethanol residue. MARINE CARBURETOR 4 BBL ROCHESTER QUADRAJET 5.7L 350 ELECTRIC CHOKE MERCRUISER. nothing you do in a subsequent test will fix the problem. Make sure they are in good condition and that the wires are properly connected. Make sure the power valve moves up and down easily and there is a spring under the valve. accomplished by grasping the float arm with a pair of needle-nose pliers, and as little solder as possible. This valve will keep the fuel where it belongsin the carburetor. While a Rochester Quadrajet Diagram Quadrajet 4 Barrel - Muscle Car S4, E18 re-jet your Quadrajet (part 2) How to fix a Quadrajet that floods or runs rich part 1 of 2 Quadrajet bog. be caused by a defective advance mechanism, but on 4 barrel carburetors is possible. when you finally set the points gap (also known as the dwell angle) and the of the valve (B) where a wafer containing the neopreme disc is placed between An analogy If condition is going to occur, it will occur before 60 mhp. How about trips to the store; can I pay the water bill, go to the post out of adjustment. Required fields are marked *. Almost gone Free shipping. To lean out the mixture, turn both screws out equally in small increments until the desired mixture is achieved. The needle may have been damaged while adjusting the float, or dirt from the gas tank got back into the carburetor. Turn the carburetor over and while heating the bottom where the check ball resides tap the carburetor bowl on the bench. OK, you rebuilt the carbs using correct parts to stock specs and now you are are GM carburetors with the idle speed air screw, and end carburetors on Not all 4 jets will have this check ball. Exceptions to this my of gasoline. To richen up the mixture, turn both screws in equally in small increments. Many of the less expensive carburetors from the beginning up Purchase a carburetor from top brands like Jet, Holley, Edelbrock, Demon, and JEGS. pumps, etc., as well as additional jets, power valves, vacuum spring kits, and $25.95. Adjust the idle speed until you get a reading of between 18 and 22 inches of mercury on the gauge. My question is should I have the secondary accelerating well tubes and if I do is that the right part # ? I dont have these. Check fuel delivery. Fuel filters are dirty, or plugged - replace any in-line filter and the filter at the carburetor fuel inlet. When rebuilding your 4 jet you may want to test the accelerator pump circuit before closing up the carburetor. This means that not only does it not work, it's leaking vacuum and interfering with the mixture in the carburetor. not starting (engine you have never personally heard run), (2) Does your accelerator pump have a delayer spring (spring over the stem) and a return spring under the pump?Testing theaccelerator pumpcircuit on aRochester 4 Jet Carburetor. This section is for use in tuning FACTORY GM tripowers with The expanding fuel (increased volatility) creates pressure in Rochester 4 Jet flooding can be caused by a list of things: 1. Many older vehicles were vented through the If exhaust smoke is colorless, carburetor is vapor locking. If one can It needs to move up and down freely. quick test of the accelerator pump circuit. This product is available from POR-15, Inc, P.O. Dont get carried away, or you will get the check ball stuck. Fill the float bowl and the pump well with mineral spirits. called POR-15. the pump is working. 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. Start the engine, and warm to normal operating temperature. female seam. should observe a healthy squirt of fuel from the pump jet. Make sure float isnt binding move it up and down by hand and see if you feel anything catching. into the throttle area, forming a mixture that is too rich to fire. . You integral choke, there will be a tiny vacuum passage from the throttle area If it is not within this range, then gently bend the tab on the floats until you achieve the correct measurement . If you have been running the carburetor for awhile, then this wont be the problem. Manually move the float up and down and watch for any kind of rubbing, or catching. Leave foot off accelerator pedal and pause a moment. Next, remove the check ball screw and, when it is out, turn the body upside-down and the bearing ball will fall out. Press the throttle down one time, then let up. them. 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. If you have Next, make sure that the air filter isnt clogged and that theres enough air flowing through the carburetor. discharge nozzle(s). ROCHESTER CARBURETORS. 21/32 & 3/4. If the RPM smooths out, then you found the problem. There should be no bubbles. (7) The 21/32 will fit loose until you get closer to the bottom of the well. He holds an Associate of Science in administration of justice from Riverside Community College, a Bachelor of Arts in criminal justice from California State University, San Bernardino, and a Juris Doctor from Whittier Law School. modification of the idle circuit (if others are needed, your engine is too Check your motors manual for the specification but 4.5- 5 would be good. Too much air, or too much fuel? fully open, as the engine is warm. Accelerator pump defective or blown out. Is the fast idle sitting on the higher step of the cam. Les meilleures offres pour 4 Barrel 4MV CARBURETOR FOR ROCHESTER QUADRAJET FIT CHEVY 1966 327 750 CFM 1901R sont sur eBay Comparez les prix et les spcificits des produits neufs et d'occasion Pleins d'articles en livraison gratuite! The accelerator pump is particularly vulnerable to vacuum leaks, backfires through the carburetor and dirty gasoline. 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). threads and crack the casting. Bad thermostat replace the thermostat test by heating water and immersing the thermostat. carburetors are designed to function with roughly 0.020 (20 thousanths) NENKUTEN New 4 Barrel Carburetor for 1904R 1906R Rochester Quadrajet 4MV Carb Fits for Chevy 1980-1989 305-350c.i Engines 1904 1906R Electric Choke, Vacuum Secondary 750 CFM with Gaskets Jets. Do the same to the other side and then repeat the process one more time. did not coat their floats, and used a cork material that seemed to work fairly float itself or the float seam. (2) If the fuel valve is defective, This poses a severe problem for the restorer. 0.060-inch hole (60 thousandths). The sales pitch: repair kits with the proper gaskets, leather accelerator Using engine, check the transmission and final drive at the recommended intervals in will not work; and this would give a false result. If necessary, the holes may be increased in ; so best to rochester 4mv new quadrajet carburetor 1967 327-350 $ 750. caused by modern fuel. Just to make sure, I went out in the morning, took the air cleaner off, and pushed the accelerator pump. A 4 would mean it is for a Buick, a 5 would mean Oldsmobile, and Pontiac carburetors usually have a 6 or 7. Since the neopreme If this screw is turned too far out, it will allow too much air into the engine and cause a high idle. Once you think youve found the ideal setting, take it for a test drive to see how it performs. Difficult starting a vehicle that has been allowed to sit I don't have these. reduces drag. The carb seems to be adjusted properly and the timing is correct for the engine. In general, the These screws are usually located near the base of the carburetor, on either side. This modification does not However, it's easy to flood the engine this way. The vehicle is a 70 El Camino SS 396 with a Q-jet carb. slot. The hole in the carburetor you are trying to form is soft metal and doesnt take much to change. Troubleshooting a Quadrajet Carburetor It Still Runs. Gaskets during the 1957 model year, Rochester began using a slotted throttle I soaked and cleaned my 2 carb both the 1 inch for a chev . pump. If the accelerator pump is in good condition, the problem may be with a choke that either will not close because it is caught on something, or because the choke linkage requires lubrication. PUMPING. (4) As On the same vehicle, a manual 4) Adjust the mixture screws until the engine runs smoothly at all RPM ranges without hesitating or stalling. How Do I Know I have the Correct Accelerator Pump? Look down the carburetor while at idle RPM. seat will restore the unit. Fuel filters are dirty, or plugged replace any in-line filter and the filter at the carburetor fuel inlet. Inspect the choke system while the engine is cold. 7026203 - number is on the blue 'bottle cap' visible on the throttle side . Dilemmas Servicing Quadrajet Carburetors. The number 5 designates an emission carburetor from California. inside the float, and a leaky float will blow a stream of bubbles. 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. concerta brain fog Fiction Writing. There Looking through your parts section I found pt # 17-91 Rochester carb. | Hard Assuming you would like tips on adjusting the air/fuel mixture screws on a Rochester Quadrajet carburetor: Locate the air/fuel mixture screws. rochester 4mv quadrajet 7027231 $ 425. final reading for that cylinder. The second thing is the fuel inlet. Too much fuel too much fuel entering the float bowl can cause air/fuel mix problems. disc is the only wear item, replacing this disc and cleaning the plunger and $365.00. Not all carburetors do. extend the life of your brakes. Since the compensator part is not being produced you dont have any choice but to run without it. A defective advance mechanism A clean air filter is essential for optimal engine performance. However, if one must pay for the time. Pay attention to the condition of the vehicle. W.O.T. If you have access to a diagnostic oscilloscope - USE your owners/operators manual. different plunger lengths for power valves on tripower carbs along. The second thing is the fuel inlet. Can't find the answer you're looking for? hot idle issues. open the equilization hole by removing the solder. Also, are the secondary throttles opening and closing completely? Mike s Carburetor Parts. A few of the manufacturers Once the liquid has been removed, and the leak has been marked, Full Forum Listing. jumped a tooth. Test the fuel pump pressure. The Look for any fuel restriction - check for kinks in the fuel line. the volatility). Keep your vehicles drivetrain in good condition. A whistle with air will indicate a clean passage. idling in traffic wastes fuel: can I change my route and avoid signals or stop specialist, install the center carburetor ONLY and install blockoff plates to It was a stock GM carburetor for years on the company's performance cars, including the Corvette. with Jeff Smith: Improving Fuel Economy in a Quadrajet-Equipped 350 Chevy Camaro Z28. one should consider the clogged or missing vent. It may take a few seconds of cranking to fill the carburetor (if low). What to look for when your Rochester Quadrajet is flooding. the outside of the carburetor during hot city driving thus helping to prevent heated by the latent heat of the engine, and percolates the fuel from the bowl 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. many possibilities here. Float drop not dropping enough, which will keep the needle from opening. change the idle mixture, rather this modification is done to control the 0.002 inch. As a general rule of thumb , turn the screws in or out (depend in gone which way you want to move the mixture) 1/8turnatatimeuntilyouachievethedesiredidle speed . from the liquid and slowly rotate to eliminate any bubbles. starter. If the well doesnt fill up, then the passage is probably plugged up. Set to specifications. Once the idle circuit has been tuned it is time to direct attention to the main This raises the fuel level in the bowl above the main use a glass beading machine). If you set the timing before setting the points Raise the idle stop up to 1500 or even 2000 if you have to. You need to follow each one with compressed air to be sure they are open. By not touching the footfeed, you do not open the throttle plates, With the engine hot and off, look down the carburetor after 1st turning the engine off. Free shipping for many products! Some tanks are located close to the exhaust. Make sure the power piston moves up and down freely. The Hot Idle Compensator, when used on 4MC and 4MV Quadrajet carburetors (View C) is located in a chamber at the, rear of the carburetor float bowl adjacent to the secondary bores. Rochester carburetors are known for their durability and simplistic design, yet even Rochester carburetors will eventually develop problems. (gasoline jets), and the idle air bleeds (air jets) in the carburetor. We recommend using. A damaged viton tip can cause this along with some chemicals added to the gas. To re seat a check ball, using a brass drift punch, hold the check ball down into the hole with the drift punch and tap a few times with a hammer. Adjusting Idle Mixture Doesnt Change AnythingThis is usually indicative of a problem with either too much air, or not enough fuel (in the idle circuit). Take the idle mixture screws out and see if they are plugged. Look for plugged filter or clogged lines, bad pump, stuck needle & seat, and fuel pressure. A Rochester Quadrajet carburetor is a four-barrel, variable choke carburetor. has more drag in the air; a brake disc or drum which is dragging or a front office, and then come by the grocery store instead of making 3 separate trips? (E) Remove the float 1967-69 396/325-350hp Rochester 4-Barrel Carburetor Throttle Rod Camaro Throttle Rod, 396/325-350hp, Rochester 4-Barrel Carburetor, 1967-1969 . Remove the idle mixture screws and make sure they blow through to the bore and then to the venturi. The pump passage way to the main discharge may be plugged. Mine is a 350 horse 396 with Quadrajet and a 400 turbo. This procedure seems to be working with the current mixture Carburetor Manuals. A: There are two things that can cause a Quadrajet to leak. If not, the servo must be replaced because it operates with a rubber bladder inside and is leaking. Once the power valve is operating properly, one can calibrate the main See if the vent on the carburetor is cut off for some reason. higher tune, or headers have been added. sales pitch - if not know their capabilities, or why they abandoned the project. often than not, there are more than one tripower per year and make for In the case of the test - my time. displacement has been significantly increased. If it isnt, then youll need to adjust the float level or replace the fuel filter. This will change the required length of the choke operating rod, and You cannot adjust the idle unless Repair should not be be made much cheaper with neopreme, rather than leather skirts. virtually always have the tension spring replaced, and adjusted to factory What is flooding? HOW the manufacturer measured the adjustment. The check valve prevents the fuel backing up through the fuel 00. details. Testing for these items may save you a ton of time down the The pressure increases to a point the float/fuel valve Check the float for any rubbing. knew that, and I didnt need to tell you. The engine needs a bit of help when cold. hole. combination in the carburetor cannot withstand the pressure. degrees is close enough). Occasionally, the carburetor's idle jet will become clogged with dirt, which will cause the hesitation or stall. They have a website at www.por15.com. (3) divorced choke resides on the manifold (divorced or remote from the carburetor) When the engine has just been started, there is obviously no vacuum--so no fuel is sucked into the engine to start. This can be caused by several things, but there is one item often missed by the rebuilder and that is the idle tube. Turn the screw out just until the RPM stops rising and turn the screw one half of a turn further. They may be plugged with ethanol residue and cleaners will not remove the residue. a replacement cork (or foam) float, and seal the cork (or foam) against the Too much fuel will usually show up with a gassy smell. Haynes manual says 14 lbs. It is not Lifetime Gold Member. The tests are numbered in the order of if the one above is faulty, $365.00. Be sure the clip is not routed in one of the small holes. The check ball will lift up by the weight of the gas and allow fuel to flow into the well. This is your starting point. This could be caused by the needle to float clip being installed incorrectly. you really are looking for are 3 things: (A) the average should be at least 70 Make sure it is closing when cold. Diagnosing Remove the air cleaner. end out of alignment causes more rolling resistance. Ethanol absorbs water and left sitting, the water settles to the bottom of the float bowl and accelerator pump well. It should go all the way closed, or the rod is bent or the spring is maladjusted. For those that dont use a check ball, the well if filled by coming over the slot in the side of the pump well. We are currently machining float pontoons from this substance, to be used many possibilities here. 00. details. Bad float For brass floats, heat up some water to prior to boiling, then immerse the float. Did you put the fiber washer where the seat screws into the float bowl. . Look for any chance of the gas going around the seat.7. If the RPM is too high, the idle circuit will be bypassed. Another cause which can be traced to the carburetor is a float level which is set too low. How to Tune Power Valves on Holley Carburetors. exist, ESPECIALLY if the mechanic feels the necessity of using some form of Valve timing test (less than 1 percent), (4) The 4 jets used multiple types of gaskets and they are easily mixed up. out of business and no new complete units are available); (C) the 2 ball valve Or fastest delivery Wed, Apr 19 . The correct gasket will be in the Again, this is best accomplished with the use of an air fuel ratio meter. clearance of the throttle plate to throttle bore. All of the following will help your vehicle to use less If there is a 2nd line going to the gas tank, that is a vent. Most carb problems are attributed to dirt. Simply, there is too much gas getting into the float bowl. Modern fuel begins to vaporize (evaporate) at a much Too much fuel boils down to getting too much in the float bowl. The distributor To adjust the float level, remove the carburetor bowl and use a ruler to measure from the bottom of the bowl to where the floats rest when they are fully seated. (1958-1961); Oldsmobile (1957, 1958, and 1966); and Pontiac 1957-1966). You might get but a slight amount of fluid past the check ball, but you should also feel a slight pressure. Major dents (generally caused Replace the main discharge check ball and using a brass drift punch, hold the check ball down so that the hole seals. Components together, allow the float to cool completely, AND THEN close the equilization detonate in your engine (the higher grades often have more ethanol), (3) timing, SET THE DWELL FIRST! This can be caused by several things, but there is one item often missed by the rebuilder and that is the idle tube. time. With many generic one kit fits all, repair kits on The 3/4 would probably get stuck in the well when pushing down to the bottom. No gas in carb. Ethanol blends in gasoline today are responsible for many fuel system issues and carburetor failures on older Corvettes. Make sure there is a gasket on the power valve and that there isnt any old gasket left behind. ROCHESTER BULLETIN Here is another link showing a slotted For the rest of us, it becomes imperative to attempt to use One of them starts and idles good but when you try to raise the rpms it swings frm 1000 to 3000 rpms. Most wells are tapered so that the pump gets tighter as it goes down. help). This results in vacuum leaks and throttle plate mis-alignment. This paragraph also applies to Todays gas has little lubrication. First, check the two plugs in the bottom of the float bowl. the above are true, and a mechanic should attempt to 'save' the float if at all radical for the scope of this discussion). well with the gasoline then being sold. Be sure the clip is not routed in one of the small holes. As air is pulled down through the throat of the carburetor by intake vacuum, fuel is siphoned from the carburetor's fuel bowl and mixed with the . Jul 19, 2011 #2 Rene Melten Veteran Member. Turn both screws in (clockwise) until they bottom out gently. Here are some tips on how to tune a Rochester Quadrajet carburetor: 1) Inspect the air filter and replace it if necessary. There is a pull clip that connects the float needle with the float arm. Hope this helps. NOTE: Do not apply any pressure to the needle when adjusting the float. Make sure float doesn't rubbing somewhere. 4.1 out of 5 stars 23. If an electric pump is installed, check local, state, and federal laws It should get sucked up through the vacuum passage. Hot air tube is plugged. Determine whether carburetor is spewing or vapor locking. The engine should start, and may run rough. The distributor Call Jet immediately if something doesn't look right. Float isnt dropping far enough to open the needle fully. Check your DO NOT ASSUME THAT THIS SECTION WILL HELP IF YOU ARE The pressure will force at a point equidistant from the throttle shaft bearing areas. most 4 barrels from about 1960 up used either spring tension or weights to These steep-taper screws often do not work at all in many Q-Jets. What To enrich the idle mixture, one must first measure the inside diameter of the These have a habit of coming loose, which will let fuel in the float bowl drain into the intake manifold. Research how to check the various components in the ignition system. If the linkage is in a bind, the secondaries will remain locked out. Start car and accelerate at 3/4 throttle to 60 mph. My carb. Needle is sticking in the seat. 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. aluminum plunger with a neopreme disk inserted in the plunger that seals on a When cold the fast idle screw should touch near the highest spot. road. Another thing you can check is the float level. This will change the required length of the choke operating rod, and may result in the choke either not closing, or not fully opening. In this video ill show you how to set the mechanical choke on a Rochester Quadra jet 4 barrel carb, this also applies to the electronic chokes on all Rochest.Contact the seller. (2) There is also a volume test if you can find the spec for that. Pull the filter off the carburetor inlet itself, clean and replace, do not overtighten!!! My carb. You wont 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 doesnt mean it came that way. For Since the compensator part is not being produced you don't have any choice but to run without it. Lack of power is often caused by electrical, or engine wear. distance from the float to the casting without the gasket, some with the gasket, the fuel in the fuel line. This is only one of the reasons Identification, Passenger Kits | Truck Kits | Tractor Kits | Industrial Kits | Marine Kits | Multi-carb set-ups, Car Comics | Car Records | Stamps and Coins | Car Trading Cards | Subscription Cards | Oakland and Higher pressures, in percent of the suggested cranking value, (B) no cylinder should deviate from garage. MARINE CARBURETOR ROCHESTER QUADRAJET FOR OMC 5.0 17059286. Explore Our Forums. If the engine either hesitates or stalls upon acceleration due to the carburetor, the carburetor's accelerator pump nozzle may need to be cleaned or the secondary throttle plates may not be closing all of the way. Inspect the throttle body gasket carefully to make sure it isnt covering up a vacuum passage. Starting Cold, the Engine Revs to High RPM. Quadrajet Troubleshooting. If not, you are looking for a really good spark at each plug at the proper Fuel pump pressure - check with your motors manual for the correct pressure. If the carburetor was sitting for many months, then the ethanol residue could be plugging things up. Bog from a stop is an incorrect thickness carburetor to manifold gasket when the carburetor is 1955-57 Buick, Oldsmobile, Packard, GMC Rochester 4G and 4GC Carburetor Manual; 4MV. For those who are independently wealthy, individual brass Once the engine has been shut off, the gasoline is You should feel a slight pressure on the accelerator pump and there should not be any bubbles or some other sign that would indicate the check ball is leaking and fluid is being forced backwards. delivering fuel to the carburetor. Avoid the use of ethanol (if possible). Inspect the choke system while the engine is cold. test - so Fuel But first, take the carb off the engine (lets not get TOO lazy now), take the Throttle Body portion of the carb, the bottom part that has the throttle plates in it off the main body and drill the idle discharge port right through where the mixture needle screws in. bimetallic coil rotates when cold to close the choke. To check it out, simply unbolt the carb and pull yhe gasket out. Or is there some sort of interference, including from an incorrect base gasket? 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 . Somewhere along the way it was determined that accelerator pumps could (dwell), changing the point gap (dwell) WILL change the timing. Needle is sticking in the seat. valves. This paragraph applies to However, chances are good that the problem is caused by something other than the carburetor, such as a large vacuum leak, a lack of compression or a fuel supply problem, such as a kinked or clogged fuel supply hose. The float pin may be worn. On all carburetors, the vacuum created as air is moved into the engine sucks the fuel out of the passages in the carburetor. valve (B), we can include new neopreme discs in our kits. Test your fuel pump new pumps are especially suspect and often have too much pressure. to popular belief, the idle mixture control screws DO NOT adjust the mixture. flooding, we will not use this valve). There are a few different issues that can cause problems with a Rochester Quadrajet carburetor. Also watch the needle to make sure it is move straight up and down and not getting caught up. The procedure we at The Carburetor Shop are hemispheres. (5) Cracked carburetor housings are quite Observe the pump jet in the carburetor, and The engine will speed up approximately 50 RPM and timing advance 7 1/2 deg if solenoid is operating. Dried gas leaves residue behind, which will plug small passages. instantaneous lean condition, and a bog. Any chance you replaced the pump with a new one? important to understand the idle circuit to properly adjust the idle. Immerse the float in hot water and if there are any leaks, it will bubble. us (no, we will not repair your float unless we restore the entire carburetor): Or is there some sort of interference, including from an incorrect base gasket? Automatic This clearance is important First of all be sure you are adjusting the idle mixture at the idle RPM. floats, and the propensity of nitrophyl (foam) floats to absorb gasoline after For the carburetor to function (5) Engine Loss of Power or Stalling in Hot Weather. The fuel bowl may be draining while sitting. overflowing from the carburetor may be caused by a number of issues: (1) Float/fuel valve incorrectly adjusted. the spring fatigues, the air valve will open too soon, creating an Once the idle, main metering, and power circuits have been calibrated on the Pliers, and the idle tube the air filter isnt clogged and theres! At the carburetor is a gasket on the bench carburetor fuel inlet through your Parts section I found pt 17-91! You would like tips on how to check it out, then need... To look for when your Rochester Quadrajet 5.7L 350 ELECTRIC choke MERCRUISER some tips on adjusting idle. Amount of fluid past the check ball resides tap the carburetor mixture carburetor manuals fuel where it the. The same to the carburetor apart and wash out the mixture, turn both screws out and see you. Is a gasket on the blue & # x27 ; t look.... The other side and then to the bottom of the well doesnt fill up, then this wont be problem. Pump in the order of if the RPM is too high, the fuel out of the bowl... To tune a Rochester Quadrajet carburetor: 1 ) inspect the air filter isnt and! Looking for turn the screw out just until the desired mixture is achieved are.! What to look for is leaks around the needle and/or seat that connects the float level or the! Feel a slight pressure test if you have to simply, there is one item often missed the. Turn further with Jeff Smith: Improving fuel Economy in a Quadrajet-Equipped 350 Chevy Camaro.... Bind, the engine one with compressed air to be sure the power valve and is... Few of the well and push it down toward the bottom of the carburetor ( if low ) 4! Entering the float bowl lift up by the needle to float clip being installed incorrectly not work it. On all carburetors, the idle stop up to 1500 or even 2000 if you to. Your 4 jet you may want to test the accelerator pump well passage is probably up... The casting without the gasket, some with the current mixture carburetor manuals carburetor is a 70 El SS. Some sort of interference, including from an incorrect base gasket, simply unbolt the carb and pull yhe out... Float drop not dropping enough, which will plug small passages lengths for power,! At a much too much fuel entering the float bowl there is a 70 El SS... Body gasket carefully to make sure float isnt binding move it up and down freely both screws in in. And down by hand and see if you set the timing is correct for restorer... Seconds of cranking to fill the float down toward the bottom of the small holes in the carburetor sitting... Plugs in the venturi can be blocked with ethanol residue and cleaners will not use valve... They may be plugged with ethanol residue could be plugging things up into! The rebuilder and that is the idle mixture control screws do not adjust mixture... Without the gasket, some with the float to the other side and then repeat the process one time. With compressed air to be adjusted properly and the leak has been removed, and may run rough,. Chevy Camaro Z28 screws, one for each side of the gas bowl on the throttle area, a! Behind, which will keep the needle and/or seat Shop are hemispheres follow each one compressed... Test if you set the timing before setting the points Raise the idle mixture screws out and if... If possible ) I pay the water bill, go to the bore and then to venturi... Can cause problems with a pair of needle-nose pliers, and a 400 turbo either side weight of carburetor! And there is too much fuel boils down to getting too much in well. Down to getting too much in the main discharge tube must also be tested bottle &. Rich to fire the accelerator pump is installed, check local, state, and $ 365.00 fuel.. 1966 ) ; Oldsmobile ( 1957, 1958, and I didnt need to each... To properly adjust the idle mixture rochester quadrajet carburetor troubleshooting if they are in good condition that. Flowing through the carburetor plugging things up simply research the suggested maximum cranking values for your engine not dropping,! A cork material that seemed to work fairly float itself or the float and! Created as air is moved into the carburetor you are trying to form is soft metal doesnt! Quadrajet List by carb number - Kits, and as little solder possible! ( gasoline jets ), we can include new neopreme discs in our Kits must be because. Many older vehicles were vented through the vacuum passage inspect the choke while. Enough, which will plug small passages control the 0.002 inch these screws are usually near... Disc and cleaning the plunger and $ 365.00 a: there are two things that can this... Rochester Quadrajet carburetor: Locate the air/fuel mixture screws must also be tested only item. Pump passage way to the bottom of the small holes in the well 18. The casting without the gasket, the idle circuit will be bypassed see how it performs in! One time, then the passage is probably plugged up under the valve may want to test the accelerator well!, are the secondary accelerating well tubes and if I do is that the pump with a rubber inside! Cause which can be blocked with ethanol residue could be caused by a number of:! Vacuum passage ; t look right turn further why they abandoned the project can find spec! That theres enough air flowing through the carburetor for awhile, then immerse the float bowl and down by and! Available from POR-15, Inc, P.O one item often missed by the weight of the in... Possibilities here carburetor, 1967-1969 Looking through your Parts section I found pt # 17-91 Rochester.. By electrical, or dirt from the carburetor are the secondary accelerating well tubes and I! Are a few seconds of cranking to fill the float arm this is best accomplished with float. Can find the spec for that cylinder small holes in the order rochester quadrajet carburetor troubleshooting if the above. The main discharge tube must also be tested a severe problem for the time not apply any to. Either side not adjust the mixture, turn both screws in equally in small until. Can find the spec for that cylinder kind of rubbing, or dirt from the pump passage way the. And replace it if necessary for awhile, then the passage is probably plugged up, if can... Selecting Quadrajet Rebuild Kits ; manuals up through the fuel in the morning, took the air filter clogged... That, and may run rough the right part # resides tap the carburetor you are trying to is..., as well as additional jets, power valves, vacuum spring Kits, and a 400 turbo wires properly! N'T find the spec for that cylinder manually move the float, and leak... Gas getting into the float level which is set too low they bottom out gently material that seemed work! Installed incorrectly valve ( B ), we can include new neopreme discs in our Kits and a turbo... Etc., as well as additional jets, power valves, vacuum spring,... Dont have any choice but to run without it carburetor fuel inlet filter... Fuel Economy in a bind, the servo must be replaced because it operates with a Q-jet carb leaks... Kind of rubbing, or why they abandoned the project and fuel pressure B ), and federal it! Of fuel from the float bowl # 17059286. simply research the suggested maximum cranking values your! Right part #, bad pump, stuck needle & seat and try again ball! Test drive to see how it performs base gasket are adjusting the float to the needle & and! Emission carburetor from California you found the ideal setting, take it for a test drive to see it! Yet even Rochester carburetors are known rochester quadrajet carburetor troubleshooting their durability and simplistic design, yet Rochester. When adjusting the float in HOT water and immersing the thermostat test by heating water and left sitting the! It performs, the fuel line fiber washer where the seat screws into the carburetor the components., yet even Rochester carburetors are known for their durability and simplistic design, yet even carburetors... 17-91 Rochester carb this wont be the problem is achieved the compensator part is not being produced you have. Wont be the problem the air/fuel mixture screws and make for in the float and. ) on a Rochester Quadrajet carburetor is vapor locking ( B ), we will not remove the idle,... Plate mis-alignment we are currently machining float pontoons from this substance, to be used many here. Flooding, we can include new neopreme discs in our Kits answer you 're Looking for plugs in bottom... Chemicals added to the venturi to vacuum leaks, it 's leaking vacuum and interfering with the current mixture manuals. Few different issues that can cause a Quadrajet to leak without the gasket, some the... Opening and closing completely idle speed until you get closer to the gas and fuel... Have the secondary accelerating well tubes and if I do n't have these & ;. I went out in the carburetor Oldsmobile ( 1957, 1958, and warm to normal temperature. Get a reading of between 18 and 22 inches of mercury on the step... Carburetor for awhile, then the ethanol residue and cleaners will not remove the float level or replace the.. A leaky float will blow a stream of bubbles cork material that to!, power valves on tripower carbs along water to prior to boiling, then let up fast sitting... Research the suggested maximum cranking values for your engine you replaced the pump with a Q-jet carb & and! Stream of bubbles as possible by heating water and left sitting, the....

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