I have a brand new DL-50 on a Hangar 9 Yak. I'm using a Mejzlik 23x8 prop. I ran about half a tank through it on the ground using a 40:1 mixture. The next day I'm flying my maiden flight and about a minute in I go dead stick. My batteries were fine but I checked my spark plug and it was very corroded. What do you guys think went wrong? Running to hot maybe?