Mantis sell one:

http://mantis.com/store/viewitem.asp?idProduct=917

Hose off all the soil, thoroughly, beforehand.

thank you yungman, (blush) I thought I looked there first...ordered one today... someone also recommended a carpet knife, which is a utility knife with a hooked blade - I think I'll do both

I made one with a piece of heavy wire and it works fine

I use a propane torch. I aim it at the bottom of the tangled mess, and burn through the stems. Then I grab the unburnt stems with a Vise grip and pull.

Don't you worry about heating the transmission too hot and effect the lube and gasket. I personally would not do that!!!

Anyone try the fish gutting hook knife? I don't know the technical name of this, it is the knife look like a hook with the inner part sharp. You can use it to hook and cut the stuff.

You want a linoleum knife (not a carpet knife):

http://www.sears.com/shc/s/p_10153_12605_00972206000P?vName=Tools&cName=HandTools,Carpentry&sName=Utility%20Knives%20&%20Cutters&psid=FROOGLE01&sid=IDx20070921x00003a

A grass sickle might work but I don't think those are sold anymore.

Yungman, I thought of the heating problem. When I am finished cleaning the weeds off, I grab the tine shaft and feel how warm it is. It's never more than comfortably warm. This is on any tiller I've ever owned. On a big tractor mount tiller, the shaft doesn't even warm up. I think it's because most of the stuff that gets wrapped around the shaft is green, and doesn't burn very well.

I've tried all kinds of stuff, and the burning method is the quickest. It works nice on string and rope too. Kinda smoky though. Don't do it in the garage.

If you want to know what serious trouble looks like, how about a 1/4" rebar wrapped around your tine shaft. My tractor mount tiller will actually wrap the rebar right around itself. It took over an hour with a hacksaw to get that thing off. Made my day. And then there was the 20 foot length of barbed wire. I lost some blood on that deal.

I forgot the best advice of all. Mow before you till! It will solve 99% of the problem. There won't be anything long enough to wrap around the shaft.

A linoleum knife and needle-nose ViceGrips.

That is funny, 1/4 rebar wrapped around!!!!

I can see torched the big tines.

lilydude- that is why I own an acetylene torch!