I have an old Z62 which was secondhand when I got it around 20yrs ago. It was fitted to a Super Duper Greenley used for glider towing and on a tow with the engine flat out it would suddenly stop after around a minute and a half, back on the ground it would start ok but do the same next time round. When not towing but just general flying using more throttle movements it wouldnt cut out.
Anyone else had similar problems or got any idea whats wrong with it?, the usual things of cleaning out the carb, changing the spark plug make no difference.