RE: MAGNUM .52 XLS fuel tank Pressure line
Hi!
Try to lean the low end needle. Most likely is the engine adjusted way off. Initial setting on my .52 is 3/4 turn open on LS, and 1 1/2 -2 turns on HS.
If you pull off the fuel line at idle (2500-3000 RPM), the engine should stop in abt 3-5 sec. If set too lean, it stops quicker. Too rich mixture and it will run for 10 sec.