Toss the stock glow plug after break-in and install a OS#8 or enya #3, the stock plug is junk. I have run a few of the MDS engines and found that the carbs were a problem on many of them. Some were fine while others were awful. QC on the carbs was spotty at best. I used 5% nitro and a prop that would let the engine wind up a bit. The MDS engines like to turn up, so don't overload it with too much prop. Use like a APC 10X6 or smaller.