TOHATSU BFT 250A Owner's Manual page 65

When you check the oil level with the dipstick, you might notice the engine oil
appears milky or the oil level has increased. If you notice either condition,
change the engine oil. See the following table for an explanation of these
conditions.
Operating Method
Running the engine below
3,000 rpm for more than 30%
of the time so the engine does
not warm up.
Frequent starting and stopping
without allowing the engine to
warm up.
Result
• Water condenses in the
engine and mixes with the oil,
resulting in a milky 
appearance.
• Unburned fuel mixes with the
oil, increasing the volume of
oil.
SERVICING YOUR OUTBOARD MOTOR
Effect
The engine oil deteriorates,
becomes less efficient as a
lubricant, and causes an
engine malfunction.
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