Other than looking ridiculous and being difficult to adapt to the fuel pump and the carburetor? Why not just use the right size tubing to start with? My FLAPS has several different diameters and lengths of pre-made steel lines, including the correct size which I believe is 5/16". I've made fuel lines with them for years. I doubt if the 3/16" line would carry enough fuel volume for full-throttle operation.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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