LOL. WD 40(I dont think) gets gummy after a long time of sitting in the engine. I personaly use the gasser type 2 stroke oil for my engines and they all last a while except for the VX-18 I had. ATF seems to be the better of them all. Also, if you run certan fuels check the bottle, I run the sidewinder mix and it has ARO in it and says NOT to use it after running.