I have a Mantis Tiller that will not pickup fuel to the carb. I have taken the carb apart, sprayed carb cleaner several times thru all the holes, ports, jets, holes under the welch plug and yes I did remove the two speed adjustment screws when I cleaned this out. I installed a new carb rebuild kit and a new primer bulb and primer base ( the carb is a Zama C1U K54) and replaced the fuel lines (the dealer gave me 'grey' colored replacement lines?) The primer bulb when pushed several times will not pick up fuel from the tank. I can hear the return to tank valve open but ???? The tiller starts and runs good if I put fuel thru the choke throat and will run till all that fuel is gone, what Gives? Can someone help!!!!!!!!!!