Sorry Hoodlum, but the 250's don't have reeds. They have a piston port engine. Kinda like a chainsaw or weed whacker.
The only thing left if you feel the jetting is right (there should be a 128 main in carb) is timing, and advance. I'm pretty sure the 79 is a 6 volt unit that has a points style ignition. If the points are out of adjustment, or the flywheel has jumped time a little it could cause the symptoms you describe. (I seriously doubt it though).
A worn needle or needle holder can also cause this problem. So can a float that isn't adjusted properly.
Eliminate one thing at a time until you get it figured out.
If you don't already have one here is a copy of the manual in .zip format. Its been a while since I looked at it, but I think it has a decent troubleshooting section.
http://g2buggy.g2-innovations.com/gentech/manuals/fl250manual.zip