Tiger Cub really hard to start, tends to stall, flames come out of exhaust

I have a Tiger Cub that's been really hard to start this year. I usually have to try many, many times. It doesn't seem to start unless the choke is more than half way open. Once it does get going, it tends to stall quite a bit. If it's been running for a while, flames come out of the exhaust.

I had similar problems last year, and I seem to remember someone saying something about the fuel shutoff solenoid. Two questions:

- is this the first thing to check?
- how do I get it disconnected? It has a grounding wire that was easy to get off, but the other wire goes into a clear plastic sheath.