Had a saw exhibit some weird behavior today, A Husqvarna 50 I have would go dangerously lean as it heated up, so much you would have to re-tune it drastically in both high and low speed. It starts easily when cold, the screws set exactly where they should be, and you can move it in all positions without an idle speed change. Within about 5-10 minutes of use it goes completely out of tune. Venting problems? fuel starvation related to heat somehow? Never had a saw do this before. +30C conditions today, so not crazy hot out. Carb mounted good and tight. My normal mix using premium, no E-10. No problems with another saw today using the same mix.