RE: engine shutting down on take off
if it was so rich to the point the engine dies then he would never get off the ground. if rich and advance the trottle it would load up and he would abort the takeoff. adjusting the plane with the nose in the air can be a good way to set it but if trying to get every bit of rpm out of it could be lean.
the first thing i do if having engine problems is a new plug and new fuel.
then check engine for leaks. Carb, head, rear cover and so on.
then pull the tank and open it up and replace all fuel line.
replace fuel line to engine.
then try again.
i have found clunks fell off, holes in line letting air in once some fuel comes out of the tank