Older Homelite 26cc trimmer hard starts & won't start when warm?

I just had someone instruct me in this forum on how to replace my flexible shafte in this trimmer. I told him the engine ran fine. Now it seems I spoke too soon when I said it was running fine. It behaves totally different since I repaired it; although, I also replaced the prime bulb which was deteriorated with a new one that doesn't seem to fit correctly. The engine will not start when choked; if it starts it is when it is not choked...then it will run until I shut it off and it won't want to restart. It's a really hard start to begin with, but after it's been running a while I seem to have to let it sit before it will start back up again. I did replace the fuel and the spark plug; I also had the carb torn apart to change the prime bulb. Everything seemed OK in the carb, but I'm certainly no professional.