ya one of them is for an oil pump so it mixes the fuel in the carb. but some of them dont have a pump so you need to plug that hose. it is the one inbetween the valve and the engine, if you dont plug it it will suck air in through there instead of the air fuel mixure and it wont run. the other tube goes through the bracket that is attached to the side of the carb and is attached to, i think the fuel intake. i dont have it infront of me but it is pretty explanitory one you plug that first hose. i hope that helps.