RE: Magnum XLS Engines
I have a Magnum .61 two stroke that I bought new. It gave me some trouble at first. Didn't seem to want to respond to the high-end needle adjustments. It would run way too hot. But after 3 or 4 tanks of fuel and some adjusting of the low-end needle it got better and better. Now it runs great! Seemed to need a little longer break-in period than some engines.
I also have a used Magnum .52 four stroke that I bought off Ebay. It has run great since day 1! I never understood why the guy wanted to sell it!