Volvo Penta V8-225, Operator'S Manual

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Less than Optimal Performance
To determine the engine’s listed power rating, all Volvo
Penta engines are tested and certified at the following
conditions:
Condition Value
Air temperature 25°C (77°F)
Barometric pressure 100 kPa (14.5 PSI)
Relative humidity 30%
Fuel 87 AKI (90 RON)
When troubleshooting a suspected reduction of power
or speed consider the test conditions above. If actual
conditions are significantly different than any of these
variables, a reduction in speed is expected. High ambi-
ent temperatures, high humidity, low pressure or low
octane fuel can all reduce power and speed.
In extreme cases these conditions can cause detona-
tion or spark knock. The engine’s computer constantly
monitors for this condition. If detonation is detected,
the computer reduces spark advance to reduce the
detonation and the engine damage it can cause.
Reducing the spark advance reduces power.
Performance of the boat as a complete package is also
based on similar test conditions. Variances in boat per-
formance can usually be traced to differences between
actual conditions and the test conditions.
The condition of the hull also influences performance.
See
Hull Weight and Boat Bottom that follow.
Hull Weight
Total boat weight is an important factor in performance.
This is a combination of the boat and the passengers
and gear that are on the boat. Any increase in boat
weight will reduce boat speed. To minimize this prob-
lem, do not store un-needed gear on your boat. Over-
loading with passengers also causes problems.
If adding a significant amount of weight to the boat,
such as generators, appliances, coolers and other
heavy items, consider the effect of the added weight
on performance.
Fiberglass boat hulls can absorb a significant amount
of water over time and can become progressively
heavier.
As the boat becomes heavier, the original propeller
(and in some cases the drive ratio) may no longer be
correct for the boat. Hull weight was a major factor in
the original selection of these components.
If boat performance has declined over time and added
weight is suspected, consult an authorized Volvo
Penta dealer to discuss the issue. Your dealer can
P0020436
Troubleshooting
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