Raw, unburned gasoline odors are usually caused by a leak somewhere. Start up in the engine compartment and makes sure all the fuel hoses are in good shape. Check around the fuel pump, filter, and hard lines for any seepage or pinholes. The carb could also have a leak or too high a float level. Moving to the rear, likely leak spots are the filler neck grommet, fuel sender seal, hard lines, pin holes in the tank and/or filler neck, gas cap, and the breather hose.