Hey James,
I bought new tires for mine at a place called harbor freight. they are online at www.harborfreight.com. You can pick up front tires for around $4 each. I bought one to try and it worked perfectly. I bought a couple more so I would have an extra or two. They have the innertubes too I found out. They are not "official" weedeater tires or tubes, but they work.
After three "spun-out" front tires though, I bought a couple of "solid-tire" wheels at Lowes though and this resolved all my tire issues fully. They were a little pricey at $32 each though (I remember they came with two sizes of spindle bearings and I had to use the bigger size).. I looked around on ebay seeking hand dolly tires (I think they were 3/4" spindles??) I will have to look.. 3/4 or 5/8.. Measure your spindles and you can see for sure. I found them there for around $10 each. I just got tired of the flat tire issue on those itty-bitty front tires, and having to repair an innertube everytime they "rolled out" of the tire and wheel on a blowout... (4" tires are a pain to unmount and mount!!!).
Let me know if that helps you out there! or any questions on that. I have unwittingly become a quasi-expert of their stupid front tiny tires.
Fellow Weedeater friend,
Stan Skaggs