RE: magnum engine problem
If you need to return the engine or carb, I know that Magnum/Global gas GREAT customer service.
I got a bad carburetor (could not be converted to Remote Needle because they accidentally glued down the needle[sm=bananahead.gif] or overtightened it) on my Magnum XLS46, which has the same carb as yours.
Their website (and Tower) lists the carb as about $50. The customer service people replaced the carb for FREE. I didn't have to pay shipping and I didn't have to mail them the broken carb. The people are great!