dad blame ethenol
 

I went to crank my old mower, I had started restoring years ago, and it would not hit a lick without carb. cleaner shot into the carb. I figured it was the old gas I had put in it before. quite a while back. I knew it would be dead, but hey its ran on old gas before. So I pulled the carb. and you wouldn't believe the gunk inside it. I have it soaking inside carb. cleaner now. It should be good to put back together after a day or 2. I am in no hurry for it. It might get used a little maybe twice a year just to keep it loosened up. That is why now I run sta-bil in all my equipment.

interesting little "experiment" ... put a couple tablespoons of 10% e-gas in a shallow pan and set it outside. in a couple days, take a gander at the reddish brown residue that's left after everything has evaporated. )))

I don't doubt that. I have had this problem with this old mower before. I just need to crank it more often. Hopefully the stabil will help also.