Put the B-12 Chemtool Total Fuel System Clean-Up (part #2616) in the gas tank first at 1 oz/gal. Then you can use the B-12 Motor Tune-Up (part #0316) a number of ways. Put it in the crankcase for dispersion of gum or deposits, in the gas tank for top cylinder lubrication at ½ oz/gal, or in the gas can for fuel stabilization, moisture dispersion, and top cylinder lube of small engines at 0.5 oz/gal (peak season) or 1.0 oz/gal (off season).