Hey Jammer, you are correct on both. Your post was a little vague on the fuel mixture.It appeared to me as if you were mentioning air/fuel mix. Oil is introduced into the 2-cycle as lubricating properties only, and the air/fuel mix should be his main concern on jetting. Oil has an actual higher BTU per unit than gas, but is crude in current state and does not help in power output. And for Tblazerdad I just wanted him to know that the 2 injection systems were similar but not identical, such as through the rubber intake manifold on 400 and the engine cylinder on the later 250's. No bashing intended [img]i/expressions/face-icon-small-smile.gif[/img]

 

Actaully there's a fitting just after the slide on the left side of the carb for the oil line. I bet the economic/after market people decided to do this. and because of this you just can't put any AF carb on, unless one decideds to run premix. HMMM....[img]i/expressions/face-icon-small-happy.gif[/img]