I have a Troy Bilt weed eater (TB22EC). Recently the primer bulb cracked. I went to my local hardware store and Lowe's. Neither place had a primer bulb the exact size as the original. I have tried 3 different sizes of pb's and none of them will pull any gas into the bulb. So before spending any more money, does replacing the bulb with one the exact size as the original matter?

Or is there a bigger issue?

I have not disconnected any fuel lines. The only thing I have done is remove the plate for the bulb.

Thank you for the help.