Servicing The By-Pass Valve - Toro 30187 Operator's Manual

Hydraulic fluid escaping under pressure can
penetrate skin and cause injury.
• If hydraulic fluid is injected into the skin
it must be surgically removed within a
few hours by a doctor familiar with this
type of injury. Gangrene may result if
this is not done.
• Keep body and hands away from pin hole
leaks or nozzles that eject high pressure
hydraulic fluid.
• Use cardboard or paper to find hydraulic
leaks.
• Safely relieve all pressure in the hydraulic
system before performing any work on
the hydraulic system.
• Make sure all hydraulic fluid hoses
and lines are in good condition and
all hydraulic connections and fittings
are tight before applying pressure to
hydraulic system.

Servicing the By-pass Valve

The by-pass valve is adjustable to ensure easy
operation with a variety of deck sizes. If the front
of the deck lifts off the ground when the upper
control bar is quickly pushed forward or the
machine is unable to drive up hills, an adjustment
may be needed.
Testing the By-pass Valve
1. Start engine and run for 5 minutes at 3/4
throttle, to warm hydraulic fluid.
2. 2. Drive the machine to a clear and level open
area such as a driveway. There should be
at least 10 feet of clear area in front of the
machine.
3. 3. Loosen the quick release levers and push
the reference bar forward to the fast position.
Lock the quick release levers to secure the
reference bar.
4. 4. Move throttle control to 3/4 throttle.
5. 5. Quickly push the upper control bar against
the reference bar. The front caster wheels
should almost lift off the ground. If front
caster wheels lift the off the ground, the
machine is too aggressive and adjustment is
required.
6. 6. Move the engine throttle to the fast position.
7. 7. Quickly push the upper control bar
against the reference bar. The front caster
wheels should lift approximately 1 inch off the
ground. If front caster wheels lift the off the
ground more than 2 inches, the machine is too
aggressive. Adjustment is required.
8. 8. If the machine accelerates slowly, and the
front caster wheels do not lift off the ground,
the machine is too un-responsive. Adjustment
is required.
Adjusting the By-pass Valve
The by-pass valve should be adjusted to deliver
best performance for the size (weight) mower you
have. The by-pass valve factory setting is 1/2 turn
out.
The following values can be used as initial settings
for different size mowers:
• 52 inch – 1/2 turn out
• 44 inch – 1 turn out
• 37 inch – 1-1/6 turn out
• 36 inch – 1-1/6 turn out
1. Loosen the large jam nut several turns
(Figure 40).
2. Gently close the by-pass valve. Do not
over-tighten the valve or the needle and seat
may be damaged. Do not exceed 50 in-lb (5.6
N⋅m) of torque to close the valve.
3. Open by-pass valve a 1/2 turn (Figure 40).
4. Tighten the jam nut to lock the adjustment
(Figure 40).
5. Repeat the Test Procedure to check for proper
operation. The by-pass valve adjustment is
very sensitive, do not adjust it more than a 1/6
turn (one flat) at a time.
6. If the machine is too aggressive or tends to
jump forward, the valve needs to be opened
further.
7. If the machine is slow to respond, the valve
needs to be closed further.
8. Repeat the Test Procedure to check for proper
operation. Re-adjust the by-pass valves until
proper performance is achieved.
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