Anyone else having trouble keeping the wing struts attached on their Rascal 110? I am using a Saito 1.80 for power and it shakes a little

The wing struts attach with a metric (2.5mm?) socket head screw on each end (1 screws into wing and 1 srews into fuse). I have used lock washers on both screws, but they will not stay in place. I could use locktite, but that's not the best choice since I'll be disassembling the plane to tak it home at the end of the day.

Are the struts functional?

Thanks for the help.
Jim