How carburetors work.
07-02-21, 06:26 PM
#1
How carburetors work.
Found this amazing video visualizing the operation of a carburetor, and I finally have an understanding how these things work. I tried understanding the concept of the carburetor in the past, but after reading a bunch of explanation, my understanding was still very vague. I even upgraded the petcock and jets on my motorcycle, but I was mostly just blindly turning bolts and following instruction without really knowing what the hell I was doing.
Of course an actual carburetor is more complex than the basic 3d printed see through model in the video, but its great to help comprehend the concept.
Of course an actual carburetor is more complex than the basic 3d printed see through model in the video, but its great to help comprehend the concept.
07-04-21, 07:21 PM
#2
Lexus Fanatic
Thanks for the post. 
Carburetors as we know them were basically 1930s technology, and, IMO, the auto industry waited 10-15 years too long to replace them, first with throttle-body electronic fuel injection (one injector for the whole engine), then injection into the intake manifold, then individual port-injection, then DI (Direct-Injection) into the cylinder, which is considered state of the art today, although that system can sometimes lead to carbon-buildup.
I say that the industry waited a decade or more too long to change from carburation to EFI (which, on average, it did in the mid-late 1980s), because it was plain that engines were having noticeable drivability problems (I remember them well) as early as the early 1970s from overly-lean mixtures, not enough choke when cold, and various other problems. And, on some Chrysler products (particularly two-barrel carbs), you had troubles as far back as the early 60s with icing/stalling problems from manifold heat-risers that didn't work properly and overly-lean chokes. Sometimes the choke would stick all the way open or closed, and you would have to physically move it yourself. Ford, GM, and AMC products were, in general, somewhat more reliable in the 60s-vintage carbs, but they also sometimes had problems. Then, in the 1970s and 80s, came emission controls, that screwed the carbs up even more with electronic choke-devices, unadjustable settings, sealed-screws, etc.....that simply did not allow engines to start reliably, run smoothly, or make any real power. The conversion to EFI should have taken place in the early 70s instead of the mid-80s.....my goes is that most mainstream makes stuck with carbs as long as they did because they were cheaper, although some luxury bands like Cadillac (and some mainstream European brands) converted several years before the rest of the industry did. In the 1970s, the technology was there for more primitive versions of EFI, which, although not the equal of later systems or of what we have today, would have been far better then carbs. Mechanical fuel-injection had been tried by Chevy as far back as 1957 on some their high-performance engines, but proved unsuccessful.
Carburetors as we know them were basically 1930s technology, and, IMO, the auto industry waited 10-15 years too long to replace them, first with throttle-body electronic fuel injection (one injector for the whole engine), then injection into the intake manifold, then individual port-injection, then DI (Direct-Injection) into the cylinder, which is considered state of the art today, although that system can sometimes lead to carbon-buildup.I say that the industry waited a decade or more too long to change from carburation to EFI (which, on average, it did in the mid-late 1980s), because it was plain that engines were having noticeable drivability problems (I remember them well) as early as the early 1970s from overly-lean mixtures, not enough choke when cold, and various other problems. And, on some Chrysler products (particularly two-barrel carbs), you had troubles as far back as the early 60s with icing/stalling problems from manifold heat-risers that didn't work properly and overly-lean chokes. Sometimes the choke would stick all the way open or closed, and you would have to physically move it yourself. Ford, GM, and AMC products were, in general, somewhat more reliable in the 60s-vintage carbs, but they also sometimes had problems. Then, in the 1970s and 80s, came emission controls, that screwed the carbs up even more with electronic choke-devices, unadjustable settings, sealed-screws, etc.....that simply did not allow engines to start reliably, run smoothly, or make any real power. The conversion to EFI should have taken place in the early 70s instead of the mid-80s.....my goes is that most mainstream makes stuck with carbs as long as they did because they were cheaper, although some luxury bands like Cadillac (and some mainstream European brands) converted several years before the rest of the industry did. In the 1970s, the technology was there for more primitive versions of EFI, which, although not the equal of later systems or of what we have today, would have been far better then carbs. Mechanical fuel-injection had been tried by Chevy as far back as 1957 on some their high-performance engines, but proved unsuccessful.
Last edited by mmarshall; 07-04-21 at 07:24 PM.
07-04-21, 08:18 PM
#3
Thanks for the post. Carburetors as we know them were basically 1930s technology, and, IMO, the auto industry waited 10-15 years too long to replace them, first with throttle-body electronic fuel injection (one injector for the whole engine), then injection into the intake manifold, then individual port-injection, then DI (Direct-Injection) into the cylinder, which is considered state of the art today, although that system can sometimes lead to carbon-buildup.
I say that the industry waited a decade or more too long to change from carburation to EFI (which, on average, it did in the mid-late 1980s), because it was plain that engines were having noticeable drivability problems (I remember them well) as early as the early 1970s from overly-lean mixtures, not enough choke when cold, and various other problems. And, on some Chrysler products (particularly two-barrel carbs), you had troubles as far back as the early 60s with icing/stalling problems from manifold heat-risers that didn't work properly and overly-lean chokes. Sometimes the choke would stick all the way open or closed, and you would have to physically move it yourself. Ford, GM, and AMC products were, in general, somewhat more reliable in the 60s-vintage carbs, but they also sometimes had problems. Then, in the 1970s and 80s, came emission controls, that screwed the carbs up even more with electronic choke-devices, unadjustable settings, sealed-screws, etc.....that simply did not allow engines to start reliably, run smoothly, or make any real power. The conversion to EFI should have taken place in the early 70s instead of the mid-80s.....my goes is that most mainstream makes stuck with carbs as long as they did because they were cheaper, although some luxury bands like Cadillac (and some mainstream European brands) converted several years before the rest of the industry did. In the 1970s, the technology was there for more primitive versions of EFI, which, although not the equal of later systems or of what we have today, would have been far better then carbs. Mechanical fuel-injection had been tried by Chevy as far back as 1957 on some their high-performance engines, but proved unsuccessful.
Carburetors as we know them were basically 1930s technology, and, IMO, the auto industry waited 10-15 years too long to replace them, first with throttle-body electronic fuel injection (one injector for the whole engine), then injection into the intake manifold, then individual port-injection, then DI (Direct-Injection) into the cylinder, which is considered state of the art today, although that system can sometimes lead to carbon-buildup.I say that the industry waited a decade or more too long to change from carburation to EFI (which, on average, it did in the mid-late 1980s), because it was plain that engines were having noticeable drivability problems (I remember them well) as early as the early 1970s from overly-lean mixtures, not enough choke when cold, and various other problems. And, on some Chrysler products (particularly two-barrel carbs), you had troubles as far back as the early 60s with icing/stalling problems from manifold heat-risers that didn't work properly and overly-lean chokes. Sometimes the choke would stick all the way open or closed, and you would have to physically move it yourself. Ford, GM, and AMC products were, in general, somewhat more reliable in the 60s-vintage carbs, but they also sometimes had problems. Then, in the 1970s and 80s, came emission controls, that screwed the carbs up even more with electronic choke-devices, unadjustable settings, sealed-screws, etc.....that simply did not allow engines to start reliably, run smoothly, or make any real power. The conversion to EFI should have taken place in the early 70s instead of the mid-80s.....my goes is that most mainstream makes stuck with carbs as long as they did because they were cheaper, although some luxury bands like Cadillac (and some mainstream European brands) converted several years before the rest of the industry did. In the 1970s, the technology was there for more primitive versions of EFI, which, although not the equal of later systems or of what we have today, would have been far better then carbs. Mechanical fuel-injection had been tried by Chevy as far back as 1957 on some their high-performance engines, but proved unsuccessful.
07-05-21, 07:08 AM
#4
Lexus Fanatic
This sounds a lot like what is happening to EFI now. Engineers designed a beautiful, simple device but outside forces made them "improve" it for the sake of fuel economy and emissions. The carburetor on my motorcycle works flawlessly, and I absolutely love the instant, direct throttle response.
One reason carbs on motorcycles tend to work better than on cars is that, to my knowledge, they were never subjected to emission controls that restricted the air/fuel mixtures to too-lean values for optimal engine response.
07-05-21, 11:06 AM
#5
Yep, exactly what I said. Carburetors seem to work gloriously without government intervention. The same thing is happening to the modern EFI systems, the evermore strict emissions and economy regulations force the manufacturers to make these systems more sophisticated, more expensive, less reliable and probably less efficient in the long term.
07-05-21, 11:17 AM
#6
EV ftw!!!
Yep, exactly what I said. Carburetors seem to work gloriously without government intervention. The same thing is happening to the modern EFI systems, the evermore strict emissions and economy regulations force the manufacturers to make these systems more sophisticated, more expensive, less reliable and probably less efficient in the long term.
Don't know why you are saying EFI systems don't work or suck. I can't imagine how bad the car would have been with a dinosaur tech like a carburetor. this is so backward thinking.
07-05-21, 11:29 AM
#7
The EFI on my GS400 worked flawlessly for over 2 decades with not a single visit to any dealer/mechanic.
Don't know why you are saying EFI systems don't work or suck. I can't imagine how bad the car would have been with a dinosaur tech like a carburetor. this is so backward thinking.
Don't know why you are saying EFI systems don't work or suck. I can't imagine how bad the car would have been with a dinosaur tech like a carburetor. this is so backward thinking.
What the EPA did to they carburetor, they are now doing to EFI and other components of modern ICE engines.
Meme below related.
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07-05-21, 03:45 PM
#10
Another great video comparing types of fuel delivery, including the carburetor. I absolutely love the fascinating simplicity of the carburetor, it eliminates the need for the fuel pump, fuel filter, airflow sensor, o2 sensor, injectors, and the fuel management computer.
Few motorcycles are still using carburetors because they haven't been subjected to the emissions nonsense, and because with typical two cylinder engines the uneven fuel distribution across cylinders is not really a concern.
Few motorcycles are still using carburetors because they haven't been subjected to the emissions nonsense, and because with typical two cylinder engines the uneven fuel distribution across cylinders is not really a concern.
Last edited by Och; 08-24-21 at 12:59 PM.
07-05-21, 05:31 PM
#11
I believe that NASCAR realized that, in 2012, almost no cars sold in the USA had carburetors. So they were following the technology - better fuel efficiency and the like. EFI was supposed to reduce engine stress, but 2012 & 2013 had more blown engines and other damage than in the years prior to EFI implementation. It took some time to tweak EFI for the cup cars.
But, if you like seeing flames come out of the exhausts when coming into corners, you'll have to be content with watching the carbureted Xfinity series & Camping World trucks. Pretty much no flames out the of the Cup cars with EFI.
But, if you like seeing flames come out of the exhausts when coming into corners, you'll have to be content with watching the carbureted Xfinity series & Camping World trucks. Pretty much no flames out the of the Cup cars with EFI.
07-05-21, 08:15 PM
#12
Lexus Fanatic
I believe that NASCAR realized that, in 2012, almost no cars sold in the USA had carburetors. So they were following the technology - better fuel efficiency and the like. EFI was supposed to reduce engine stress, but 2012 & 2013 had more blown engines and other damage than in the years prior to EFI implementation. It took some time to tweak EFI for the cup cars.
07-06-21, 09:56 AM
#13
Found this amazing video visualizing the operation of a carburetor, and I finally have an understanding how these things work. I tried understanding the concept of the carburetor in the past, but after reading a bunch of explanation, my understanding was still very vague. I even upgraded the petcock and jets on my motorcycle, but I was mostly just blindly turning bolts and following instruction without really knowing what the hell I was doing.
Of course an actual carburetor is more complex than the basic 3d printed see through model in the video, but its great to help comprehend the concept.
https://youtu.be/toVfvRhWbj8
Of course an actual carburetor is more complex than the basic 3d printed see through model in the video, but its great to help comprehend the concept.
https://youtu.be/toVfvRhWbj8
I really miss the fantastic NOISE my 800CFM Quadrajet made when I floored the gas pedal in my 7.5 litre Firebirds !
08-24-21, 06:32 PM
#15
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