Norm, they usually unscrew, if the footpiece has a hex.
The other way to check is to pull off the fuel pump cover. That's the one on the side of the carby, visible in the above shot. Then you'll be able to do the suck/blow test. And then that pump diaphragm should really be replaced, but they're under $5. P/No 272538.
As regards that gasket, there are three different types, and all are available singly. However, two are cheap - $3 or less, and the other is ~$9. You'll have to go through the IPL to work out which one you need.
