Crankcase Vacuum Test; To Test Crankcase Vacuum With Manometer - Kohler Command PRO EFI Series Service Manual

Troubleshooting

CRANKCASE VACUUM TEST

Carbon Monoxide can cause severe nausea,
fainting or death.
Avoid inhaling exhaust fumes. Never run
engine indoors or in enclosed spaces.
Engine exhaust gases contain poisonous carbon
monoxide. Carbon monoxide is odorless, colorless,
and can cause death if inhaled.
A partial vacuum should be present in crankcase when engine is operating. Pressure in crankcase (normally caused
by a clogged or improperly assembled breather) can cause oil to be forced out at oil seals, gaskets, or other available
spots.
Crankcase vacuum is best measured with either a water manometer or a vacuum gauge (inches of water gauge only).
Complete instructions are provided in kits.

To test crankcase vacuum with manometer:

1. Insert rubber stopper into oil fi ll hole. Be sure pinch
clamp is installed on hose and use tapered adapters
to connect hose between stopper and one
manometer tube. Leave other tube open to
atmosphere. Check that water level in manometer is
at 0 line. Make sure pinch clamp is closed.
2. Start engine and run no-load high speed.
3. Open clamp and note water level in tube.
Level in engine side should be a minimum of 10.2
cm (4 in.) above level in open side.
If level in engine side is less than specifi ed (low/no
vacuum), or level in engine side is lower than level in
open side (pressure), check for conditions in table
below.
4. Close pinch clamp before stopping engine.
Condition
Crankcase breather clogged or inoperative.
Seals and/or gaskets leaking. Loose or improperly torque
fasteners.
Piston blow by or leaky valves (confi rm by inspecting
components).
Restricted exhaust.
22
WARNING
KohlerEngines.com
Rotating Parts can cause severe injury.
Stay away while engine is in operation.
Keep hands, feet, hair, and clothing away from all
moving parts to prevent injury. Never operate engine
with covers, shrouds, or guards removed.
To test crankcase vacuum with vacuum/pressure gauge
(inches of water gauge only):
1. Remove dipstick or oil fi ll plug/cap.
2. Install adapter into oil fi ll/dipstick tube opening,
upside down over end of a small diameter dipstick
tube, or directly into engine if a tube is not used.
Insert barbed gauge fi tting into hole in stopper.
3. Run engine and observe gauge reading.
Analog tester–needle movement to left of 0 is a
vacuum, and movement to right indicates a pressure.
Digital tester–depress test button on top of tester.
Crankcase vacuum should be a minimum of 10.2 cm
(4 in.) of water. If reading is below specifi cation, or if
pressure is present, check table below for possible
causes and conclusions.
Conclusion
NOTE: If breather is integral part of valve cover and
cannot be serviced separately, replace valve
cover and recheck pressure.
Disassemble breather, clean parts thoroughly, check
sealing surfaces for fl atness, reassemble, and recheck
pressure.
Replace all worn or damaged seals and gaskets. Make
sure all fasteners are tightened securely. Use appropriate
torque valves and sequences when necessary.
Recondition piston, rings, cylinder bore, valves and
valves guides.
Check exhaust screen/spark arrestor (if equipped). Clean
or replace as needed. Repair or replace any other
damaged/restricted muffl er or exhaust system parts.
WARNING
62 690 05 Rev. E