I have a QT-50 that I eliminated the oiler and mix the fuel 50 to 1 and use the oil tank as a fuel reserve with a shut off valve between the 2 tanks. I recommend you make sure the fuel tank is completely clean of rust and then clean the carburetor multiple times, Replace the fuel lines and eliminate the stock air filter, it restricts the air flow a bunch. I installed a K&N styles air filter for much better flow. Remove the muffler and put it in a fire or your barbecue and heat it up to 700 degrees for an hour and burn all of the oil out of it. My engine ran so rich from the factory that it would not run at all when hot. It would bog down and barely idle if idle at all. After doing all of these items mine ran great and never stalled when hot. It will run 34mph on flat ground and I weigh 185lbs. I have never had a problem with my Stator/charge coil and I don't use a battery.