Yamaha F2.5A Service Manual

Also see for F25A: Service manual Owner's manual Service manual Owner's manual Owner's manual

Contents

POWR Power unit5-7 69M3E11Checking the compression pressure1. Start the engine, warm it up for 5 min-utes, and then turn it off.2. Remove the engine shut-off cord fromthe engine shut-off switch on the tillerhandle.3. Remove the grommet and spark plug,and then install the special service tool tothe spark plug hole.CAUTION:Before removing the spark plug, blowcompressed air in the spark plug well toclear out any dirt or dust that may fall intothe cylinder.4. Close the fuel cock and air vent screw,fully open the throttle, pull the starterrope 3 times, and then check the com-pression pressure.NOTE:Do not pull the choke knob when checkingthe compression pressure.5. If the compression pressure is belowspecification, add a small amount ofengine oil to the cylinder, and then checkthe pressure again.NOTE:• If the compression pressure increases,check the piston and piston rings for wear.Replace if necessary.• If the compression pressure does notincrease, check the valve clearance,valves, valve seat, cylinder sleeve, cylinderhead gasket, and cylinder head. Adjust orreplace if necessary.Disassembling the manual starter1. Remove the choke knob assembly 1.2. Remove the drive plate 2 and drivepawls 3.WARNINGThe sheave drum can pop out. Hold thesheave drum with your hand, and thenpull it out.Compression gauge 1:90890-03160Minimum compression pressure(reference data):700 kPa (7.0 kgf/cm 2, 102 psi)S69M50601S69M5080233