The Drawbacks of a Simple Carburetor
1) At a very low speed, the mixture supplied by a Simple Carburetor is so weak that it will not ignite properly and for its enrichment, at such conditions some arrangement in the carburetor is required to be made.
2) The working of simple carburetor is affected by changes of atmospheric pressure. Carburetors used in aircraft are to be provided with altitude control, as the rich mixture is unnecessarily available, due to less density of air.
3) The working of simple carburetor is affected by changes of atmospheric temperature. If the setting is done in winter season, it will be found to give too rich mixture in the summer. This is happened due to less density of air with the rise of temperature to a greater extent than the density of fuel.
4) It gives the proper mixture at only one engine speed and load, therefore, suitable only for engines running at constant speed increase or decrease ,the quantity of fuel issuing out will change and not match the velocity of air flowing through the venturi and proper mixture is not take place. To overcome this various modifications have to be made in simple carburetor.
5) In simple carburetor, the mixture is weakened when the throttle is suddenly opened because of Inertia effect of the fuel which prevents the proper quantity of fuel from flowing immediately.