A kit assembly for converting an existing carburetor assembly for a vehicular combustion engine to an improved carburetor assembly having an open loop manually adjustable system for selectively controlling the air-fuel ratio supplied to said vehicular combustion engine;
- wherein said vehicle has ground-engaging drive wheel means, power transmission means for conveying power from the engine to said wheel means, and a source of fuel;
- wherein said engine is provided with induction passage means of which said first-mentioned carburetor assembly comprises a portion for supplying motive fluid to said engine;
- wherein said first-mentioned carburetor assembly comprises body means and separable first fuel reservoir means, and wherein said carburetor body means comprises first fuel passage means therein for conveying fuel from said first fuel reservoir means to induction passage means;
- said kit assembly comprising second fuel reservoir means, said second fuel reservoir means comprising housing means carrying second fuel flow passage means for flowing fuel from said second fuel reservoir means to said first fuel passage means when said first fuel reservoir means is disassembled from said carburetor body means and replaced by said second fuel reservoir means, said first fuel flow passage means and said second fuel flow passage means when operatively connected to each other serving to define carburetor fuel conduit means, a plurality of fuel flow restriction members being calibrated differently from each other so that the rate of fuel flow through one of said restriction members is different from the rate of fuel flow through an other of said restriction members for the same pressure head, wherein a selected one of said plurality of fuel flow restriction members is employed for placing in series flow relationship with said carburetor fuel conduit means, cyclically openable and closeable valving means operatively carried by said second fuel reservoir means, said valving means being in said carburetor fuel conduit means and effective to controllably alter the rate of metered fuel flow through said carburetor fuel conduit means, and manually controlled adjustment means operatively connected to said valving means, said manually controlled adjustment means being effective to selectively control the relative percentage of time that said valving means is opened and the relative percentage of time that said valving means is closed in order to thereby selectively alter the rate of metered fuel flow through said carburetor fuel conduit means and to said engine.