RE: DA50 - Hard to Start, Idle Unreliable
What's the plug look like. It should be a darkish tan color. If it's lighter than that you are too lean, if it's darker then too rich.
I'd also look at the location of the ignition box. Make sure it's not in line with the muffler. After 5 minutes you could be overheating the box to the point it does not like to run correctly and you'll get a deadstick.
Also verify all fuel components including the carb pump and pop-off diaphrams.
You could also fly without the cowl on and see what happens