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Carburetor Tips – What You Need to Know

General Carburetor Tips and Tricks

Carburetor Tips


The following snippets are information that we have collected that might help you get past a problem, or better yet side step a problem. ——- Most problems being attributed to carburetor problems are usually caused by bad timing, worn spark plugs, loss of compression, poor fuel delivery, or a clogged air cleaner. Check these things 1st before tearing apart your carburetor.

  • What to use for a cleaner? We here at Mike’s Carburetor Parts use an ultrasonic cleaner, then a soda blaster when necessary. For the average person, I would get a gallon of carburetor dip at your favorite parts store, or as we like to do use Simple Green. Follow the directions on the can. Leaving your parts soaking too long may damage the metal on your carburetor, discoloring it. For Simple Green not more than 4 hours.
    After soaking your carburetor wash with hot water to remove all of the chemical. 
    Blow out every passage. Ethanol leaves residue behind that normal cleaning will not remove.
  • Carburetor Is Flooding Obviously flooding is caused by too much fuel getting into the cylinders. Assuming you didn’t pump the gas pedal too much, there are only a few ways to get too much fuel. The float bowl is getting too high. These are the most likely causes.The needle and seat is not closing. Most likely there is dirt causing it to stick open, but the needle could also be defective.The float level is incorrect.Gas is getting inside the float making it heavier than normal.Carburetor unloading isn’t correct. Depress the throttle all the way. The choke plate should be opening
  • Just Rebuilt Your carburetor and It’s Flooding? If you just rebuilt the carburetor, then take it back apart and inspect all of the parts to make sure they are where they should be. Most needle and seats require a gasket between the seat and the carburetor. Without this, the fuel will bypass the needle and seat. Test the float (see the videos). Do you have a black Nitrophyl float and did you replace it when rebuilding your carburetor. You should have because Nitrophyl floats tend to absorb fuel over time. We automatically replace Nitrophyl floats at rebuild time. Sorry, but you usually don’t get a choice between Nitrophyl and brass. Those days are gone. US companies only make one or the other.
  • Hesitation on start up – If you don’t get a hesitation, or bog when cruising and stepping on the gas, then the idle adjustment might be the problem.
  • The Engine Hesitates When Accelerating. Check the electrical system 1st, especially the distributor advance. Most likely the accelerator pump is defective. Rebuild the carburetor.
  • Hot Starting Problems Having problems starting your vehicle when it is hot and shut off. It could be due to the lousy gas we now have. Gas has a lower boiling point so it is liable to boil over temporarily flooding the engine. Back in the day we would stomp on the gas pedal all the way to the floor, then crank the engine, but if the fuel is boiling over, then that will just let in even more gas. Instead of doing that, crank the engine without stepping on the gas. Crank for a few seconds, count to 5, 1001, 1002…. Press the gas pedal about 1/3, but do it slowly. If the engine now starts, run at high RPM to burn the excess gas. 
  • Engine Surges Fuel restriction. Check the lines for bends and kinks. Replace any badly worn hose. Dirt, or water in the fuel. Clean out the gas tank and change the fuel filters.Main jets may the the wrong size. This would be due to someone changing them recently.Vacuum leak. Check the carburetor throttle to make sure it isn’t loose in the throttle body. Might be a leak at the intake manifold, or perhaps where the carburetor mounts to the manifold. Fuel level is too high, or too low. Check the float level.
  • Choke Problems When the choke isn’t opening like it should:
    • For the thermostatic type of choke with the metal coil – heat up some water and place the choke in the water. It should look like it’s unwinding. If it doesn’t, then replace the choke. Electric choke – Simply hook up the two leads to the choke to a 12 volt source. The choke should open fairly quickly.Some models have the choke mounted in the manifold. The heat from the manifold heats up the coil making the choke open. Assuming you have already tested the choke in hot water and it works fine, but doesn’t work when on the car, then chances are the manifold isn’t heating up the choke. This is probably due to the manifold being clogged around the choke area.
  • Tips on Removing and Replacing Your Carburetor One of the most helpful thing you can do while removing your carburetor is to get your digital camera out and take pictures of every step you take, then put the pictures on your computer for later viewing. Take pictures from every angle including several close ups. I do this on every carburetor I take apart on the bench. Any time I have a question, I refer back to the pictures.Lacking a digital camera, make a drawing as accurate as possible that will show where things go.Mark your vacuum lines with masking tape, labeling each one.Stuff a rag, or towel down the carburetor throat to prevent you from dropping anything down the carburetor. You don’t want to be forced to remove the manifold, or heads looking for that small screw.When removing bolts and screws, start them back into the base unit so you have the correct size bolt later.Do yourself a favor and use flared nut wrenches to remove the fuel line.After the carburetor is removed, stuff the manifold opening with something to keep foreign material out of the manifold.Remove the base gasket from the manifold. Keep in order to match it up with the new gasket. There can be very suttle differences in some carburetor gaskets.Clean the old gasket off of the manifold. Be careful what you use so that you don’t damage the manifold metal while scraping. A dremmel tool works good here.If your vehicle has been sitting for a year or more, drain the gas tank. The gas is probably stagnant and will ruin an otherwise good carburetor rebuild. Better yet would be to remove the gas tank and have it boiled out.Change any fuel filters before running the new carburetor. When bolting the carburetor back to the manifold, don’t over tighten, or you may warp the carburetor base. Don’t tighten more than 10 lbs. That isn’t very much.In summary mark, map, label and be patient. You will have a smooth carburetor job.
  • Does your carburetor need to be rebuilt? One simple test you can perform on most carburetors is to adjust your idle mixture. The engine should respond to your adjusting the idle mixture screw as long as the idle RPM is set. If not, then the carburetor probably needs to be cleaned.Another indication could be when your carburetor is flooding. You might see the fuel flooding into the carburetor, or perhaps you are getting a strong gasoline smell while running.Surging can be another indication. This results from plugged carburetor circuits. Fuel comes and goes, which causes a surging action. Does your fuel smell like varnish? When a carburetor has been sitting full of gasoline for a year or more without being run, then you will most likely need to have the carburetor cleaned along with draining your gasoline and changing the fuel filters.When you try to accelerate does your engine hesitate? This is an indication that your power circuit is defective.
  • Replacing a Motorcraft 2100 automatic choke with an electric choke. All you need is one of our choke thermostat replacements. Replace the automatic choke thermostat with the new electric thermostat. Just follow the instructions included in each electric choke conversion kit. 
  • Check Ball is stuck in the float bowl I just bought your rebuild kit for a carter ball and ball carb. As i was taking the carb apart i noticed that whatever dingbat rebuilt this thing before me got the check ball stuck in the hole (the one with the clip) and for the life of me i cannot get it out. any ideas? i feel like i have tried everything. i would hate to have to buy another float bowl for the carb because of this stupid problem. Any advice you have would be great. thanks!
    • Turn the bowl upside down and apply heat on the outside of the bowl near the check ball. Gently tap the bowl on your work bench while heating. The check ball almost always falls out. Worst case – See if you can drill a small hole in the bottom, poke it out with a wire, then seal the hole with JB Weld.

How to remove a stuck check ball:

  • Ethanol means we need to burn more fuel to get the same mile. 10%, or more depending on how much ethanol is mixed with the gas. When thinking about a bigger fuel delivery, start thinking 10% bigger, but be careful. Too much more can be detrimental. We recommend using the manufactures specs when adjusting things like the float.
  • Removing frozen parts – Try applying heat around the outside of the part, but be careful especially on the aluminum parts. They melt without warning.
  • Needle & seat – any pressure on the needle could damage the viton tip.
  • Carburetor repair while on the car – very dangerous thing to do. You could drop a small part down the bore resulting in removing the intake manifold, or head.
  • Accelerator Pump Well – Ethanol gas does not provide the lubrication gas used to, which is hard on the accelerator pump and and can cause it to fail. Polish the pump well with crocus cloth to provide the smoothest possible pump glide.
  • Metering rods do not fit tight in the main jet. They restrict gas not shut if off.

For specific information about your carburetor visit our Technical section for your particular carburetor.

Updated on 04/13/2022

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