2-24 PERIODIC MAINTENANCE
"
Disconnect the safety lanyard from the emergency stop
switch prior to cranking the engine.
This will prevent any residual fuel discharged from the
cylinders from being ignited by a spark discharged
from the spark plug cap.
CYLINDER COMPRESSION
Cylinder compression :
Standard : 1000 – 1400 kPa (10 – 14 kg / cm
2
,
142 – 199 psi.)
Max. difference between any other 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
following :
• 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. (R model)
• Disconnect the throttle limiter rod from throttle drum. (Tiller
handle model.)
(7) • Move and hold the throttle lever in the full-open position.
(R model)
• Move and hold the throttle control grip in the full-open
position. (Tiller handle model.)
(8) While cranking the engine with the starter motor or recoil
starter, note the maximum compression pressure reading
on the gauge for each cylinder.
(9) Reinstall parts removed earlier. (spark plug, side lower
cover, etc.)
Throttle
limiter rod
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