5245 fuel cap

My newly acquired 1987 5245 just lost lower and quit, even though the fuel gauge says half-full and the engine sounded fine. want to verify that there's fuel in the tank, but the cap won't turn! Is there a trick to doing this?
Also, if the problem is not low fuel, any suggestions as to what else might the problem be? Thanks. Quinn

The fuel caps on these tractors can be very difficult to remove, its due to the big "O" ring sticking to the top of the tank and jamming in the threads of the cap. Carefully use a pump wrench or better still a filter removing tool to get the cap off and get a thinner O ring.
As regards the other problem, check the gauze filter in the glass on the lift pump, if there is any water in the bowl then suspect the main fuel filters may be blocked, if so change them.
I have known one to stop with a dead fly in the banjo bolt on the suction side of the lift pump, so check that. hope this helps, Dave

I just removed the other double posting.