When mower warm the hydrostatic drive forward and reverse fails
Leave mower to cool down the unit then works ok

Hylton, June 2012

The unit is worn. As the oil gets hot, it gets thinner, and the (worn) pump can no longer generate enough pressure to operate it properly.

A thicker grade of oil will provide a temporary fix, but really it needs to be rebuilt, or replaced.

phil_saunders(a)bigfoot.com

Phil Saunders, June 2012