How a carburetor works, schemes and explanations

This video explains, not in too much detail, how a 28mm Walbro diaphragm carburetor works (using mainly schemes to point out what happens inside). It explains what occurs at the venturi, what the butterfly valve is for, how the needle doses the amount of fuel, and how does the diaphragm slide adjust itself.

Category:

Autos & Vehicles

Tags:

• carburetor
• carburettor
• carburator
• carburatore
• carburatori
• carburador
• carb
• walbro
• engine
• explanation
• understand
• venturi
• choke
• continuity
• fuel
• intake
• butterfly
• valve
• throttle
• CV
• bing
• dellorto
• mikuni
• keihin
• stroke
• carburation
• motorcycle
• car
• motor
• injection
• injector
• motorbike
• bike
• weber
• barrell
• bendix-technico
• stromberg
• evinrude
• holley

[CompagniaDellaRuota]

This vid made my day

[arctor08]

@CompagniaDellaRuota forse eri sarcastico, ma mi fa piacere vedere che anche qualche connazionale abbia visto questo video!

[CompagniaDellaRuota]

@arctor08 No non ero sarcastico, anzi! Da tempo cercavo un video che mi spiegasse chiaramente e in poche parole il funzionamento di un carburatore!! Ero sincero, giuro. Tra l'altro non sapevo fossi italiano, grande!

[arctor08]

@CompagniaDellaRuota hahaha ma grazie mille!!

[Trialanderror502]

Were you in I Am Legend?

[minicopilot]

Great accent and delivery! Very informative clip! You should be an actor or work for NASA!

[divyankumaran]

very good explanation...:-)

[Hooverdarnit]

@arctor08 I changed the springs to the air intake valve and exhaust valve, not any springs in the carburetor.

After putting in new valve springs, and setting the gap between the rocker arm and valve spring, it still misfired at higher speeds/rpms.

While trying to figure out what was wrong, I noticed the enricher/auto choke had separated from the carburetor whent eh bolts vibrated out over time.

I put the enricher back on. Can't take a test ride now, it's snowing.

[arctor08]

@Hooverdarnit mmh.. maybe while rebuilding the carb after having replaced the springs, you may have misplaced some jets? There is a screw which regulates the fuel at low apertures. Perhaps you rescrewed that to a wrong position (this is made so that it can be adjusted by screwing it more or less). This doesn't seem too much the case though, since it would affect low revs more than top power. Check any problems with rebuilding and with the full power system, such as main jet ect. What carb is it?

[Hooverdarnit]

@arctor08 Thanks for your input. I recently replaced two broken valve springs. After putting them in, the scooter ran better than new, for about a day. Then it started misfiring at higher rpms.

I checked the valve gaps and saw they shifted somewhat. I reset the valve gaps tight, and right. But still the scooter misfired at higher speeds.

I saw two small bolts in a depression on top of the engine, then saw the auto choke (enricher) off the carburetor. You think I found the problem?

[arctor08]

@Hooverdarnit I'm not entirely sure if it is possible to lock this added fuel flow to "on", but it does seem to be the case, as it would explain the problems at high rpm!

[arctor08]

@Hooverdarnit Sorry I thought you meant that you had actually lost the choke valve. Which was a stupid assumption, as I don' think 150cc have a separate valve for the choke! Then I think that your automatic choke is not a real choke, meaning that it doesn't reduce airflow, but rather, it richens the mixture by increasing the amount of fuel aspirated. So if your connection to the autochoke is broken, it might have locked to "on", richening the mixture which would be the cause of misfiring.