We had to use our 10HP QR-25 Quincy compressor a lot today and it is
95 degrees or so. When it gets hot, for some reason it unloads and
runs, but does not pump air. After it cools down, it starts and seems
to pump just fine. Then after a while it unloads and no longer runs.

The only things that I could suspect would be rubber membranes that
push on the unloaders, any other idea?

thanks