My R75/5 was running-oddly as I got home the other day, I thought I had a piece of trash in the carb-somewhere. I pulled off the float-bowls to dump them and flush the carbs out and the level seemed REALLY-LOW so I checked the tank.
I'm going to put some gas in it and see if it runs better!!
I think someone's messing with you...sneaking over and removing some gas. Better watch for that!!