I will need some help with the carb as it's continuing failure is the reason this weed eater is going to be an airplane. The guy who fixed it last time said that the walbro carbs only last about a year
An airplane engine really does need to be easy to start.
I don’t agree with your mechanic. Carburetors don’t really wear out but they do get dirty from time to time. Pumper carbs are extremely susceptible to trash accumulating in a brass screen in the carb. In addition it is almost impossible to avoid some trash when transferring fuel from pump to can and then to airplane or weed eater. The clunk filters used in weed eaters are good but they also need replacing occasionally.
To be successful you will likely need to learn to service and clean the carburetor.
Bill