For some of us the building and converting challenge is a major the part of the hobby,the operation a portion of the whole picture,not the entire picture.I like building as much as operation,I see guys get abused all the time for doing something other than drop some dough on the most popular purpose built object,the end result is another batch of RCers ushered right out of the hobby.Good Job!

Don't critisize me for enjoying my hobby.

Back to the engine problem,check the crank case seals,sometimes they leak when they get hot.