Checking The Compression Pressure; Disassembling The Manual Starter - Yamaha F2.5A Service Manual

POWR

Checking the compression pressure

1. Start the engine, warm it up for 5 min-
utes, and then turn it off.
2. Remove the engine shut-off cord from
the engine shut-off switch on the tiller
handle.
3. Remove the grommet and spark plug,
and then install the special service tool to
the spark plug hole.
1
CAUTION:
Before removing the spark plug, blow
compressed air in the spark plug well to
clear out any dirt or dust that may fall into
the cylinder.
Compression gauge 1:
90890-03160
4. Close the fuel cock and air vent screw,
fully open the throttle, pull the starter
rope 3 times, and then check the com-
pression pressure.
NOTE:
Do not pull the choke knob when checking
the compression pressure.
Minimum compression pressure
(reference data):
700 kPa (7.0 kgf/cm
5. If the compression pressure is below
specification, add a small amount of
engine oil to the cylinder, and then check
the pressure again.
5-7
Power unit
S69M5060
2
, 102 psi)
NOTE:
• If the compression pressure increases,
check the piston and piston rings for wear.
Replace if necessary.
• If the compression pressure does not
increase, check
valves, valve seat, cylinder sleeve, cylinder
head gasket, and cylinder head. Adjust or
replace if necessary.

Disassembling the manual starter

1. Remove the choke knob assembly 1.
2. Remove the drive plate 2 and drive
pawls 3.
2
3
WARNING
The sheave drum can pop out. Hold the
sheave drum with your hand, and then
pull it out.
the valve clearance,
3
S69M5080
69M3E11