Yamaha 2CMH, Rigging Manual

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8-5
FUEL SYSTEM VACUUM PRESSURE STANDARD
LOWEST VACUUM PRESSURE STANDARD
The lowest vacuum pressure must be fulfilled as below at an atmospheric temperature of 20°C
(68°F) and higher.
* Be sure to measure the vacuum pressure which is within specification at the idle and the wide-open throttle,
after the breaking-in period has been completed.
Engine breaking-in operating conditions : 10 hours
^ 2-stroke carbureted models : Use a 25:1 pre-mixed fuel.
^ 2-stroke electronic fuel injected models : Use a 50:1 pre-mixed fuel, and supply with oil injection.
^ HPDI models
: Use straight gasoline (only supply with oil injection)
^ 4-stroke models : Use straight gasoline.
Larger fuel filters installed onto a boat may lower the fuel vacuum pressure to –20.0 kPa (–15 mmHg) and
under. Therefore, follow the instructions mentioned above to rig the boat properly so that the fuel vacuum
pressure is within specification.
If the vacuum pressure does not surpass –10.7 kPa (–80 mmHg) at wide-open throttle, use a clear hose to
check fuel for air bubbles mixed.
Idle: 0 kPa to –10.7 kPa (–80 mmHg)
WOT: –10.7 kPa (–80 mmHg) to –20 kPa (–150 mmHg)