04 800 fuel issues.

[rotax3006]

went riding today and had mostly a pretty good day. towards the end of the ride the sled started to bog/cutout going up hill. I still had plenty of gas but under a hard load or any uphill the sled would run out of gas/die. It runs good on the level and going slightly downhill. Im thinking i need a new fuel pump or vaccum lines. The sled idles fine and starts good just going up hill is the problem. Any advice is greatly appreciated.
Thanks
Bill
PS lots of new snow in the crazies. (montana)

 

[rotax3006]

one other thing that came to mind is that the fuel line is run right between the the 2 coolant lines that go to the heat exchanger. The sled has a van amberg tunnel. under heavy load the engine coolant might be getting hot enough to boil the gas in the fuel line. That would cause a vapor lock and an out of gas problem. Any other thoughts?