referring more particularly to fig1 and 3 of the drawing , hot water is transmitted from the cooling system on engine or motor 16 ( which includes radiator 10 , water pump 14 , and heater 32 ) through hot water line 12 to hot water inlet 18 of vaporizer 20 . the hot water is introduced into heat exchanger 22 of the vaporizer . the hot water is forced through heat exchanger 22 and out through return water outlet 28 back to the engine via water return line 30 . after the car &# 39 ; s engine is warm , solenoid valve 34 may be electrically opened and solenoid valve 36 closed thereby diverting the liquid fuel from fuel line 38 to vaporizer inlet line 40 into fuel reservoir tanks 42a and 42b , which are mounted on the sides of vaporizer 20 . in alternate embodiments , valve 34 may be eliminated and the inlet line 40 may always be open . the level of the fuel in the fuel reservoir tanks 42a and 42b is controlled by fuel float valves 44a and 44b ( see fig5 c ). the fuel inlet line 40 terminates at fuel float valves 44a and 44b . when the fuel level drops , the valves are opened and more fuel enters fuel reservoir tanks 42a and 42b . it will be apparent to those skilled in the art that fuel float valves 44a and 44b are mounted in opposite directions . this mounting technique will have the effect of counteracting any yaw or pitch which may result from rapid maneuvers of the automobile in which vaporizer 20 may be mounted . heat radiates from the heat exchanger 22 , heating some of the fuel in the pool to a vapor state . the fuel vapor then rises from vapor compartment 120 through spacer grill 52 and through holes 50 into vapor mixture compartment 54 . outside air enters the vaporizer 20 through an air inlet system . as air enters the inlet system it passes through one of three separate sections of vaporizer air filter 56 and proceeds through air inlet 58 into vapor compartment 120 or through air inlet 60 and control valve 62 into vapor mixture compartment 54 . air may also be drawn into vapor compartment 120 through sparge tube 64 . sparge tube 64 draws air into vapor compartment 120 down into the fuel area and thereby assists in the vaporization thereof . sparge tube 64 also acts as a surge retarder and thereby prevents unwanted sloshing of the fuel . the vapor - air mixture is transmitted through vapor outlet 69 through vapor line 70 to the carburetor 72 . check valve 74 is located below vaporizer air filter 56 in the air inlet 58 . the check valve , shown in fig4 a and 4b , has two discs , upper disc 76 and lower disc 78 . lower disc 78 is suspended by piston 80 below the upper disc . the lower disc has a diameter less than the diameter of air conduit 58 while the upper disc 76 has a diameter equal to the diameter of the air conduit 58 . upper disc has five check valve holes 82 arranged around the termination 84 of the piston . in the operating , down position , air passes through holes 82 and around the perimeter of lower disc 78 into the vapor compartment 120 . in the case of a backfire , the lower disc 78 is forced up against the upper disc 76 effectively closing the air supply into and out of the air inlet 58 from the vapor compartment 120 . spring 85 holds the lower disc 78 up in the closed position when there is no air flow as seen by the arrows in fig4 b . this prevents the flow of vapors through the filter 56 when the engine is stopped . also located in air conduit 58 is control valve 75 . control valve 75 and control valve 62 are both vacuum operated butterfly valves . in the embodiment of the invention actually constructed , control valves 75 and 62 are operated utilizing engine vacuum ; however , it is within the intended scope of this disclosure that alternate methods of control , including , but not limited to , electric , electromechanical or electronic microprocessor based control systems may be utilized to operate control valves 75 and 62 . control valve 75 has the effect of increasing or decreasing the amount of vapor created in vaporizer 20 , over and above that minimum amount created by means of air which enters via sparge tube 64 , by metering the amount of air allowed to enter vapor compartment 120 . air entering vapor compartment 120 through control valve 75 is distributed through air manifold 77 . air manifold 77 is constructed with small perforations in its upper surface and larger holes in the lower surface . experimentation has shown this configuration will aid in fuel vaporization . control valve 62 is utilized to control the richness or leanness of the vapor mixture by adding air to the vapor mixture in vapor mixture compartment 54 . fig5 a , 5b , 5c and 5d depict the novel configuration of fuel reservoir tanks utilized in the illustrated embodiment of my invention . fig5 a shows a side view of vaporizer 20 with fuel reservoir tank 42b . overflow tubes 43c and 43d prevent the level of fuel present in vapor compartment 120 from rising too high under the vacuum created by carburetor suction . overflow tubes 43c and 43d are present at either end of fuel reservoir tank 42b to compensate for nonhorizontal positioning during automobile maneuvering . fig5 b and 5d depict the connection of fuel supply lines 47a and 47b to fuel supply header 45 . as depicted in fig5 d , the fuel supply lines are connected to fuel reservoir tanks 42a and 42b at opposite ends . this connection configuration , along with the opposing float valve configuration previously discussed , will have the effect of negating transient changes in attitude of vaporizer 20 . carburetor air filter 86 is fitted to receive vapor line 10 which terminates in air filter intake 88 and it is through this intake that the air - fuel vapor is introduced into the carburetor 72 . carburetor air filter 86 is depicted in fig6 . air filter intake 88 also includes control valve 90 . control valve 90 is utilized to control the aperture of air filter intake 88 . during cold start operation , when the engine is utilizing liquid fuel , control valve 90 opens and allows outside air to enter carburetor 72 . when the temperature of the cooling system of the car is sufficiently high to permit gas vaporization , control valve 90 is closed and valves 34 and 36 shift positions . liquid fuel is no longer utilized by carburetor 72 and vaporized fuel enters air filter intake by means of vapor line 70 . control valve 90 is vacuum operated in the embodiment disclosed and may be enabled utilizing an electric solenoid at the point where operating temperatures will permit vaporization . again , as discussed above , alternate embodiments of the fuel vaporization techniques taught in this application may utilize electrically operated control valves in place of vacuum operated valves . in an embodiment not shown in the accompanying figures , a small line may be inserted into carburetor air filter 86 to detect the vacuum present at the carburetor intake port . the vacuum thus detected may be utilized directly or indirectly to control any or all of the vacuum operated control valves depicted herein . the embodiment shown and described above is only exemplary . i do not claim to have invented all the parts , elements or steps described . various modifications can be made in the construction , material , arrangement , and operation , and still be within the scope of my invention . the limits of the invention and the bounds of the patent protection are measured by and defined in the following claims . the restrictive description and drawing of the specific example above do not point out what an infringement of this patent would be , but are to enable the reader to make and use the invention .