About the best way to test a magneto is see if there is a "kill wire" connected to the magneto.
If there is such a kill wire, unplug the kill wire from the magneto and see if you get spark with that wire disconnected.
If you get spark when the wire is disconnected, search for a rubbed (or chewed....mice) spot in that wire, or for a defective kill switch (stuck in the off position).
If you have not checked the entire length of the spark plug cable back to the magneto, check that for signs of damage or chewing.
Mice especially like to gnaw on rubber covered wiring.
If you have been testing using the spark plug from the engine, it's possible that you have a bad plug, and they are cheap enough to try a new one to see.

Thanks for the reply.
Kill wire is unhooked. I don't have spark to the points. Could a bad condensor cause this.

Yes, it can. But you can remove the condensor lead and check for spark to test that.
The condensor is there to extend the life of the contact points by stifling the arc over after the coil fires.
A condensor that is shorted to ground will prevent a spark.
A condensor that is open will shorten the life of the contact points.

Thanks Mownie. I'll unhook the condensor and try that. If I still have no spark I assume the coil would be bad.
Is there any way to check that.

The entire procedure we have been discussing IS CHECKING the coil (which is aka the magneto).

all the previous suggestions apply.

if this is equipped with ignition points, inspect the contacts for oxidation. Points may be closing, but may not be transferring electrical current.

It was oxidation on the points causing the problem. I could not see it while the points were in the mag. When I removed the points I saw it so I cleaned them up with a fine file and bingo, she ran.
Thanks to all for the help.
Now another question. Has anyone ever used one of these old Gravely's with a stump grinder attachment? If so, how well do they work?
Also I read somewhere that I would need to install a remote air cleaner. Is this true? Mine has the old oil bath.