POWR Power unit5-3 6D81G11Power unit 5Checking the compression pressure1. Start the engine, warm it up for 5 min-utes, and then turn it off.2. Remove the engine stop lanyard from theengine stop lanyard switch on the remotecontrol box.3. Remove the spark plug wire cover and allspark plugs, and then install the specialservice tools into a spark plug hole.CAUTION:Before removing the spark plugs, blowcompressed air in the spark plug well toclear out any dirt or dust that may fall intothe cylinder.4. Fully open the throttle, crank the engineuntil the reading on the compressiongauge stabilizes, and then check thecompression pressure.5. If the compression pressure is belowspecification and the compression pres-sure for each cylinder is unbalanced, adda small amount of engine oil to the cylin-der, and then check the pressure again.NOTE:• If the compression pressure increases,check the pistons and piston rings for wear.Replace if necessary.• If the compression pressure does notincrease, check the valve clearance, valve,valve seat, cylinder head gasket, and cylin-der head. Adjust or replace if necessary.Checking the oil pressure1. Remove the flywheel magnet cover.2. Place a rag under the oil pressure switch.3. Remove the oil pressure switch, and theninstall an oil pressure gauge 1 to the oilpressure switch installation hole.NOTE:Use a general pressure gauge.4. Start the engine and warm it up for 5 min-utes.5. Check the oil pressure. Check the oilpump, oil leakage, and oil strainer ifbelow specification.Compression gauge 1: YU-33223Compression gauge extension 2:YB-06563Minimum compression pressure(reference data):860 kPa (8.6 kgf/cm 2, 124.7 psi)S6D8511012Oil pressure (reference data):510 kPa (5.1 kgf/cm2, 74.0 psi) atengine idle speedS6D851201
