PERIODIC MAINTENANCE 2-28
A
Disconnect the safety lanyard from the emergency stop
switch prior to cranking the engine.
This will prevent any residual fuel discharged from the
cylinders being ignited by a spark discharge from the
ignition coil.
CYLINDER COMPRESSION
Cylinder compression :
Standard : 1300 – 1600 kPa (13 - 16 kg / cm
2
,
185 – 228 psi.)
Max. difference between any two cylinders :
100kPa (1.0 kg / cm
2
, 14 psi.)
NOTE:
Figures shown are guidelines only, not absolute service limits.
Low compression pressure can indicate one or more of the fol-
lowing :
• Excessively worn cylinder wall
• Worn piston or piston rings
• Stuck piston rings
• Poor seating of valves
• Ruptured or otherwise damaged cylinder head gasket
TEST PROCEDURE
(1) Start engine and allow to warm up, then shut engine off.
(2) Remove the STBD / PORT engine side lower cover.
(3) Remove all spark plugs.
(4) Install the compression gauge into the plug hole.
09915-64510 : Compression gauge
09915-63210 : Compression gauge adaptor
(5) Disconnect the safety lanyard from the emergency stop
switch.
(6) Disconnect the remote control throttle cable from the throttle
lever.
(7) Move and hold the throttle lever in the full-open position.
(8) While cranking the engine with the starter motor, note the
maximum compression pressure reading on the gauge for
each cylinder.
(9) Reinstall parts removed earlier. ( spark plug, side lower
cover, etc.)
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