Well, I think I finally figured it out.
I started replacing the coils yesterday, and when I took the cover off, I saw a giant rat nest and dead rat on the cooling fins of the left cylinder. It was completely packed full of dirt and grass. Spent 15 min cleaning it out and then gave it a test run in the super tall thick stuff.
Wasn’t too hot out but it didn’t seem like it was struggling anymore. So hopefully problem is solved.
