RE: OPS question
Hey Carl,
If you could post some pictures of your two needle setup it would be helpful. The information HJ provided is a good ballpark. Depending on your altitude, 3.5 to 4 turns is probably a safe needle setting to START your engine. Now, RUNNING it there for an extended period of time is another issue altogether. If you haven't already, I recommend joining International Waters, post pictures and ask your question there. You will have access to some of the best information on OPS engines on the web. Not a slam on RCU, just a good group of experienced nitro guys who are familiar with the old OPS engines.
Good Luck.