I have an Iseki TS1910F (similar to a Bolens G194). Unless something else is happening that I am not understanding, it should be a simple adjustment of the brake rod (connected to the brake pedal). My manual reads as follows:

1) The free play of the brake pedals is from 15mm to 20mm (about a 1/2-in. to 3/4-in.) at the top of the pedal. Both pedals should actuate their own brake with the same pressure. If not, all should be adjusted by means of the brake rods.
2) When the adjustment is finished, lock the rods securely with the lock nuts.

HTH.

Here are some photos from my manual in case adjustment won't correct the problem. Hopefully the link below works. If it does, the 8 photos may be in reverse order so open the last first and so on:

Here is a link that might be useful: brake system pics

looks like I posted twice. please disregard this one

This post was edited by larso1 on Thu, Jun 20, 13 at 10:56

If, in fact, it were to turn out that the shoe lining was worn thin, brake shoes of this type can be easily relined by a brake shoe rebuilder. Of course, the shoes would have to be removed and forwarded to such a brake rebuilder, but most large cities have at least a few firms that do this, and inexpensively too.
It is also possible (read the manual text) that oil has leaked into the brakes and fouled the linings, causing them to be ineffectual.
If so, the oil leakage would have to be deal with first.
If oil contaminated, it is very iffy whether cleaning the shoes with brake cleaning solvent would restore effectiveness of the shoes.
Oil soaked shoes would preferably be replaced (or relined) as the best option over attempted cleaning with brake solvent.