I have two DLE 20's. The first one I bought in May 2015,the second one in April 2016. The first one serial # F17868 was a problem right out of the box. Being my first gas I blamed it on teething problems. It took 5, 14 oz.tanks on a test stand to get it run. I put it in a Great Planes Super Sky Bolt. It worked perfectly for 15 flights before it quit in mid flight. I checked it out on the test stand and could not find any thing wrong it run through 4 tanks of fuel. Put it in a Phoenix Models T-34 first flights went great one minute and fifteen seconds in to the third flight it quit dead. It didn't seize it turns over freely. The second engine serial # F18966 started on the third blip of the starter. have it in the 2001 original Hanger 9 Super Cub I have over thirty flights on it and I'm using the DLE plug that can with the engineThe first engine I changed to the CM-6 plug everyone has been raving about seen no difference. Baffled!