I own 2 ASP engines... they are the same as (Magnum) I have a 61 2 stroke and a 61 four stroke, both ran great from the beginning. Though now my 4 stroke isn't running very well at the moment, (had about 50 flights on it), it idels fin then when I give it full throttle it seems like it's starved for fuel and quits... but after talking to some people they say it is just some low end and upper end adjustments which you have to do with most engines. I would buy one again... and my 61 4 stroke is real easy on fuel ( not a gas guzzler)