Troubleshooting CRANKCASE VACUUM TEST 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. 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. To test crankcase vacuum with vacuum/pressure gauge: 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. Condition Conclusion 17 66 690 01 Rev. C KohlerEngines.com WARNING Carbon Monoxide can cause severe nausea, fainting or death. Avoid inhaling exhaust fumes. Engine exhaust gases contain poisonous carbon monoxide.
Carbon monoxide is odorless, colorless, and can cause death if inhaled. WARNING 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. Crankcase breather clogged or inoperative. 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. Seals and/or gaskets leaking. Loose or improperly torque fasteners.
Replace all worn or damaged seals and gaskets. Make sure all fasteners are tightened securely. Use appropriate torque valves and sequences when necessary. Piston blow by or leaky valves (confi rm by inspecting components). Recondition piston, rings, cylinder bore, valves and valves guides. Restricted exhaust. 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.