I fly in 100 degree plus heat all the time and it doesn't seem to bother my OS 160 FT much. I do use on board glow and that makes a ton of difference. I've never had a jug flame out and low end needle valve settings are not so critical.

With my other non-onboard glow twins, I've found that after 2-3 hours of flight time they begin to run very reliably. Before that, lots of jug flame-outs and forced landings. I have to remember to keep the throttle up!

I highly recommend the on-board glow systems (I use ElectroDynamics). This has been my first experince with them and I'm sold.