I'm guessing you're all stock - if so, check your float - it could be sticking - that's supposed to be a pretty common problem. you should check your fuel pump too - and change your fuel filter.
That's where I'd start. If there's water in your system, you'd see the problem throughout your running, not just under one set of circumstances. There's something freaking out that's caused by your angle of incline - if the float is sticking, it's not getting any fuel to the intake...and if you're fuel pump is weak or fuel filter is plugged, well, that would starve your engine of fuel too, though I'd suspect that's much less likely - but you never know.
If you think you've got water in there from some other activity, you should at least put in a bottle of HEET just for good measure.
