Repair Topics / Engine Carb

Engine Carburetor Questions and Answer

This category contains featured questions as examples. They relate to most vehicles.

Question: 1976 Toyota Landcruiser FJ55 350 Chevy mileage: unknown. Hi. Carburetor is running out of fuel when under a load. I have stopped the vehicle as soon as the motor leans and quits. Checked the carburetor fuel bowl (350 Holley) and no fuel. The truck has 2 tanks and a mechanical type switch. This happens on both tanks. I have tried 2 pumps and 2 separate lines from the switch to the pump. The pump is firewall mounted. Turning the ignition on after it stalls gradually fills the bowl again for a restart.

The pump is giving about 60 liters per hour from a basic flow test I did. The voltage seems ok at 13.5 volts and steady. I have checked the needle and seat, cleaned out carburetor etc. It idles fine, accelerates fine, but just runs out of fuel when under a load for a while. I'm suspect of the needle and seat, as I can't see what else it could be. But the needle seems quite free and the float level is correct. There is a lot of fuel pressure right at the carburetor inlet after it cuts too. I'm baffled...HELP! Mark

Answer: Electric fuel pumps are good pushers but do not do well pulling the fuel. Try relocating your electric fuel pumps as close to the fuel tank as possible. Keep them as low as possible also. Make sure the tanks are properly vented so as to be sure you are not forming a vacuum as you draw fuel out.

Question: 1986 Chevy Celebrity SW V6 mileage: 46,000. Engine starts but tends to die or stall out when trying to accelerate. Have changed the fuel filter, but it didn't help. A local mechanic here in Sitka, AK told me it probably needs a new carburetor - apparently, there's some kind of electronic devices in the carburetor that cannot be fixed here. He wants to charge me $500 for a new carburetor--Is it possible to get a rebuilt one somewhere for less than that? Thank you for your help-Eric

Answer: Have your mechanic check for the availability of a rebuilt carburetor. Also, your local Chevrolet dealer should have the individual parts that go in the carburetor.

Question: 84 Plymouth 2.6 mileage: 140,000.  This van has been having problems off and on for approximately 6 months.  The carburetor is flooding but the engine is not stalling.   It has low power and is guzzling gas.  Extremely low gas mileage.  A service person said it was the catalytic converter; it was replaced and hasn't cured the problem.  It is running better but not right.  Also is there another catalytic converter inside the manifold.  Also tried a new oxygen sensor but couldn't find it to replace.  The engine is a Mitsubishi 2.6 litre what else could it be.  Thanks   

Answer: If your carburetor is flooding it probably is caused by a failing needle and seat inside the carburetor or a bad float.  Also, check for a vacuum leak.  The catalytic converters fail if the carburetor is running to rich due to the extra fuel.  Fixing the carburetor-flooding problem should be done before replacing any of the catalytic converters.  We have not worked on your model car for a long time so we are not sure, but believe that there is "pre-cat" in the manifold.  If there is, it will be obvious because of the large bulge in the manifold.

Question: 1987 Honda CRX 1.5 mileage: 116,000.  The car sat for four months because it needed a head gasket replaced. I did the repair and now it does not want to stay running. It is as if it is starving for gas. If you keep pumping the gas pedal, it will just idle. If you spray carburetor cleaner in the carburetor it will run. Float problem or not?

Answer:  From what you describe, it sounds like you need a carburetor overhaul. In addition, check for vacuum leaks.

Question: 1966 ford bronco 170   mileage: 0.  Have a new motor and have replaced the fuel filters/fuel pump/ fuel line drained the tank and cleaned it replaced the intake to carburetor gaskets and all vacuum line and checked the timing.  It idles fine but when I try to accelerate down the road it acts like it is starving for fuel and the gas filter goes almost dry.  If I disconnect the fuel line between the carburetor and the filter, it seems to be pumping plenty of fuel.  If it is the carburetor, can I replace it with a new one instead of a rebuilt (autolite 1100/1101 1 barrel) help?

Answer:  Scope the engine and check point dwell and coil output.  Check fuel pump pressure.  A new carburetor should work just as good as a rebuilt one.

Question: 1983 Toyota Tercel 3A mileage: 150,000. I live in Flagstaff, Arizona, Elevation 7000 feet. First the car gets poor fuel mileage and I believe is running very rich (strong exhaust smell). The spark plugs are always fowling. I have been told it needs to be Altitude Adjusted. Would that help and how would I do that? Second Question: In the winter the water temperature never gets warm enough for the heater to work. Do I need to install a different thermostat and what kind?

Answer: Sounds like your carburetor needs to be rebuilt or replaced. Installing a 180-degree thermostat should help the heater work better.

Question: Holley Projection 2 bbl throttle body carburetor. Will not start, believe it's getting too much fuel, how do I adjust it? Part # 34R11109B. Please reply as soon as possible, thank you, HELP!

Answer: Sorry we are not familiar with that injection system. Holley's service hot line should be able to help you.

Question: 1970: VW Super Bee bug 1600 mileage: 2000 rebuilt: just wondering what would be the right adjustment for gas and air mixture on carburetor? Thanks

Answer: The idle mixture should be adjusted with an exhaust gas analyzer to ensure proper emissions. If we remember right, there are two adjustment screws close together. The big one being idle speed, the small one, idle mixture. To get it close, turn the idle mixture adjustment screw in (clock-wise) until the engine speed drops. Back out adjustment to obtain the highest idle speed. Turn in 1/8 turn. It should be very close.

Question: 1976 Dodge p/u 318 mileage: high. I need to know how to adjust a 2-barrel carburetor for my p/u. I installed a rebuilt one ...when cold it doesn't want to hold an idle...truck fells like sluggish when I go up hills and when I accelerate from a stop it hesitates I just took the carb out of the box and put it on ...I think the carb was a holly.

Answer: Make sure the main jets in the carburetor are the proper size for your truck. From what you describe, it sounds like your carburetor is too lean. In addition, check to see that the float level is correctly set.

Question:   I have a '81 Malibu with a 305 cubic inch engine with a two-barrel Carburetor. While driving at approximately 40-55 MPH engine suddenly loses power (no sounds/as if stalled). As the speed falls below 40, the engine kicks back on. This repeats if trying to accelerate again. I have replaced the fuel pump, rebuilt the carburetor, and changed the distributor and coil. While "power-braking" the engine, the fuel enters the carburetor for about one minute then the engine dies. It acts as if it is starving for fuel. Could a hose collapse from the fuel tank cause this condition? If not, what could?

Answer: Check for fuel in the carburetor when the engine dies after power braking to isolate the problem to the fuel system. Some possible causes include: 1. Cracked fuel hoses at the tank of pump, 2. Partially plugged fuel pick-up filter in the gas tank, 3. Incorrect gas tank cap causing a vacuum in tank, 4. Alternator diode failure allowing AC voltage to ignition coil. (Try test-driving with the alternator disconnected.), 5. Faulty ignition module in Distributor.

Repair Topics / Engine Carb

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