Hi Roger. I would be inclined to replace all the fuel lines. Remove the top cover and air filter if necessary to access the carb(make sure the fuel is drained out the tank!) make a note or take a photo of where each line goes to and comes from. It should be quite easy
to remove the carb , normally a couple of nuts. You can buy fuel lines very easily . Pull out the old lines . Cut the new lines to the same length to replace each. It would be a good idea to replace any gaskets. You can how to fit fuel lines into the tank on you tube ! I am not familiar with Qualcast saws but all saws are much of a muchness . It might be worth looking to see if there are any other saws that resemble Qualcast as some makers supply different sellers. My Performance power from B & Q is the same saw as an American Homelite . So it might be worth investigating further for more info !
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