Mixed gas and altitude

[BADFISH]

I am educated in physics of nuclear nature....but I am in the middle of trying to figure this exact fiasco out with my 7.5 horse 49' champion. it runs fine in my driveway at a 25:1 ratio but when i get up to say deer creek it putters out at lower idles right away and after a while begins to not run at any thing other than "full throttle". I have a rich/lean adjustment screw on the front of my motor but as i dinked with it I had no luck in finding the "sweet spot" to get my motor running smoothly again. I am going to bump my mix to a 40:1 added to my 25:1 so i will have somewhere in the neigborhood of a 30 to 35:1 ratio and see if that does anything, some others mentioned a trick of just trimming up the motor a bit thats to say lift it a little like you would in shallow water to not bump rocks with the prop and that DOES put a less direct load on the motor at the prop and may let it run a higher RPM to keep the exess fuel/oil "blown out" of the cylinder, i can see how this works, but I can also see more pollution out of a probaly higher pollutant emittin motor as i ejects unused fuel and oil from the motor into the water.....i am trying to address my issue with a solution that will burn what i feed it, not trick it into thinking its burning it. course the trim trick would be great for gettting a slower speed out of the motor as it would have to draw water to the prop to be churned instead of just cutting into it as normal.....its the equivalent of either driving a screw straight into wood or doing it on an angle its harder to begin with but in the end you just have an angled screw in the wall.
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