I actually didn't end up replacing it! For whatever reason, it was noisy for a short time, then quieted down. I had honestly forgotten about it...it's been quiet ever since. Strange!
This is the easiest thing to check. When it dies, loosen the fuel cap. If it runs fine with the cap loose, the vent is plugged.
When you say "jump it off", do you mean you jump start it with a jump pack or other vehicle?
Thanks for the heads up. It's weird...I never got an email. Also, I just logged in and ordered a t-shirt, and the process went smoothly. Not sure what's going on.
Coincidentally, yesterday when I was teaching my son to change oil, he spilled some oil on the belt. We took it off, and washed it in a bucket of water and dishwashing detergent. Cleaned the pulleys with brake cleaner. All seems well.