Hi Guys, is it possible for a needle valve O-ring to swell up and make the needle valve really hard to turn? I have an OS 55AX and an OS 70 Surpass and after sitting a while both of them have really stiff turning needle valves. I pulled the needle valve out, the O-ring shows no damage, the threads are clean and look good, and put the needle valve back in with plenty of my after run on everything. For after run oil I use a mixture of ATF and Marvel air tool oil. Before putting the engines away for the winter last year, I squirted lots of after run oil in the carb and fuel intake nipple on the carb area. Is it even remotely possible that my after run oil is causing the O-ring to swell up, making the needle very stiff to turn?

Thanks loads,

Ernie Misner