2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 146Get this manual
IpOWRIIfriJ: IPower unit Checking the compression pressure
1Start the engine, warm it up for minutes, and then turn it offRemove the clip from the engine shut-off switch on the remote control box or tiller handleRemove the all spark plugs, and then install the special service tool to each spark plug hole
If the compression pressure increases, check the piston and piston rings for wearReplace if necessary If the compression pressure does not increase, check the valve clearance, valve, valve seat, cylinder sleeve, cylinder head gasket, and cylinder headAdjust or replace if necessary3
Checking the oil pressure
1Start the engine, warm it up for minutes, and then turn it offRemove the oil pressure switch, and then install an oil pressure gauge CD to the oil pressure switch installation holeBefore removing the spark plugs, blow compressed air in the spark plug well to clear out any dirt or dust that may fall into the cylinderS62Y5066