Air fuel mixture screws vibrating in

I had adjusted the air fuel mixture screws on my carbs 75 HP 4 cylinder Mercury Mariner. Sn A715190. Model 7075726.


It seemed to be running best at 1 & 3/4 turns out from seated. Seemed like it was running rough when idling the other day so I opened the cover to check, & they were only out about 1.5 turns. Is it possible for them to vibrate in against the tension of the springs? Lots of rough gravel roads that I have been pulling it on.

Can I use a drop of blue loctite to stop them from vibrating, or do I risk plugging up some passage in the carb?

Just stretch the springs a tad if you think this is the problem..never seen this problem in 45+years of serving Mercs

Maybe I didn't leave it out far enough. I adjusted them again. They were both evenly set at 1.5 turns out
Seemed like it was stumbling a bit at low idle trolling. I re adjusted out just a bit more to about 1 & 5/8. Seems like it needed just a bit more. I wrote down my latest adjustment, so I will know for next time.