It's 1/4 INCH - not 1/4 OPEN
Amazed that it starts at all if it's being cranked with the throttle open that much, if it does it suggests that the throttle linkage has an issue with the 1/4 open being the fix - but that would not explain the 1/2inch on hot.
Maybe we have a solution to some starting problems - errors and misprints in rewrite POHs and chec lists?