Here's a challenge for ya!

[Jim LaGuardia]

The higher the octane the better. High octane fuel will extend engine life due to less heat generated and longer burn time.
Timing can stay 3-7mm btdc and as high as 12mm as long as it does not ping.

[berger]

I found another product that is supposed to help with ethanol....

http://mystarbrite.com/startron/

[Twin Pinzies]

UPDATE:
I insulated all of the fuel lines with metallic-backed foam pipe insulation and now only run premium 91 octane fuel.
It seems to be the trick... I have no more problems with stalling, low power, and poor running any more. The only other thing that has changed is the weather got a bit cooler since it finally started to rain more here.
The trucks both run great now.

On this issue, be careful wrapping your fuel lines in conductive metal shielding! I accidently touched the fuel line on one of the starter wires and the engine block... and got a SCARY electrical spark/arc... while holding the fuel line in my hand!
I'm so lucky that I didn't catch the truck (and me) on fire!
I went back and insulated ALL the exposed wire connections on the starter (and all electrical points) that were anywhere near the fuel lines.

[JimmyC]

I had a similar situation with two saws. It turned out the gas I was buying (in early summer) was “winter blend” and would boil when the saws got hot. I believe low atmospheric pressure makes boiling happen at a lower temperature. The fuel I had trouble with was alcohol free. When I switched to the 10% alcohol summer blend stuff they ran great.