My saito 150 made a very loud bang last year as I went full throttle straight up to do a little roll at the peak. Got it down ok ,case cracked sent it to Horizon H. $235. Was fine after repair but I am presently having trouble with this same engine, stall stall otherwise the 150 is a good starting/running engine. Had trouble with the 125 and couple of 180`s (breaking in) good luck.....