fill it and forget it...... NEVER heard of a problem with mixing 2 stroke oils.... your deal may tell you not to do it, stick with our oil...... thats like saying only burn shell gas in our sled the rest will not run right! I run amsoil intersepter 99% of the time dont know what was in the sled when I got it , once in blue moon I have had to add oil at the local gas station because I forgot to fill up the oil tank.... I just run what ever they have to get me back to my trailer.......