QuestionThanks fo rthe info Ben, my Lawn Boy is a Model 81191, thr tranny I think is a 316-0500. I can certainly check the fluid level with no problem. Can you tell me how to "purge" the air? Thanks again.
AnswerRobert
Due to the effects air has on efficiency in hydrostatic
drive applications, it is critical that it be
purged from the system.
These purge procedures should be implemented
any time a hydrostatic system has been opened
to facilitate maintenance or any additional oil
has been added to the system.
Air creates inefficiency because its compression
and expansion rate is higher than that of the oil
normally approved for use in hydrostatic drive
systems.
The resulting symptoms in hydrostatic systems
may be:
1. Noisy operation
2. Lack of power or drive after short term operation
3. High operation temperature and excessive
expansion of "oil", in the latter case, oil may
overflow.
Before starting, make sure the transaxle/ transmission
is at the proper oil level. If it is not, fill to
the manufacturers suggestions outlined in the
vehicle owners manual.
The following procedures should be performed
with the vehicle drive wheels off the ground, then
repeated under normal operating conditions.
1. With the bypass valve open and the engine
running, slowly move the directional control
in both forward and reverse directions 5 to 6
times, as air is purged from the unit, the oil
level will drop and bubbles may appear in the
oil. After stopping the engine, add oil, as necessary.
Fill to the level outlined in Figure 3,
Page 7.
2. With the bypass valve closed and the engine
running, slowly move the directional control
in both forward and reverse directions (5 to 6
times). Check the oil level, and add oil as required
after stopping engine.
3. It may be necessary to repeat Steps 1 and 2
until all the air is completely purged from the
system. When the transaxle moves forward
and reverse, purging is complete.
