loss of power when warm

Finally got it up on the mountain, but it seems once it gets to operating temperature I lose all the power, trying to climb a slight hill in first gear is hard I was stuck in low the whole time. Even then I had no power it just would not rev up. when it is colder it runs like a champ climbs good and revs no problem at all.
Any idea where to start looking?

 

I would check the fuel lines to make sure it is not near anything that is hot. If it is either move it or make a heat shield.

 

Compression and then fuel. My motor did exactly as you described before I rebuilt it. I had bad head gaskets that were leaking between cylinders that caused that condition, it would run fine cold but once warmed up it wouldn't pull itself on flat land let alone a hill,

 

Thanks for the tips, i need to do something with my fuel line, it's cooper right next to the exhaust. Plus my compression sucks. I just need it to last through the winter then i will rebuild it.