Try adding some Marvel Mystery oil to all your fuel. I have tiller, riding lawn mower, push lawn mower, tiller, weed eater, 4 chainsaws, JD 4x4 Gator, 1951 JD MT, (had a power washer) & a 1996 M5400 Kubota (diesel). Only had to redo one carburetor on Stihl pole chainsaw.
I pour 2-3oz in...