Thank you a lot all. I bought it used a few months ago but I didn't operate it before I weathered it a few weeks ago. I didn't pay attention to the trucks but if they are from a GP30 it's normal they don't fit well. I'll check that and let you know.
you need to replace the trucks with the proper gp15 trucks and that will fix your fuel tank and plow rubbing problem.
I found the correct trucks. The issue is fixed. With the correct metal parts it's all good!!! Thanks a lot all for your help!