Getting Started; 20-Hour Break-In Period; After The Break-In Period; End Of First Season Checkup - Mercury 350 MAG Manual

If full‑throttle operation is below the recommended range, the propeller must be changed to prevent loss of performance and
possible engine damage. On the other hand, operating an engine above the recommended operating RPM range will cause higher
than normal wear and damage.
After initial propeller selection, the following common problems may require that the propeller be changed to a lower pitch.
• Warmer weather and greater humidity cause a loss of RPM.
• Operating in a higher elevation causes a loss of RPM.
• Operating with a dirty boat bottom causes a loss of RPM.
• Operating with increased load (additional passengers, pulling skiers) causes a loss of RPM.
For better acceleration, such as is needed for waterskiing, use the next lower pitch propeller. When not pulling skiers, do not
operate at full throttle when using the lower pitch propeller.

Getting Started

20‑Hour Break‑In Period
IMPORTANT: The first 20 hours of operation is the engine break‑in period. Correct break‑in is essential to obtain minimum oil
consumption and maximum engine performance. During this break‑in period, the following rules must be observed:
• Do not operate below 1500 RPM for extended periods of time for the first 10 hours. Shift into gear as soon as possible after
starting and advance the throttle above 1500 rpm if conditions permit safe operation.
• Do not operate at one speed consistently for extended periods.
• Do not exceed 3/4 throttle during the first 10 hours. During the next 10 hours, occasional operation at full throttle is permissible
(5 minutes at a time maximum).
• Avoid full throttle acceleration from idle speed.
• Do not operate at full throttle until the engine reaches normal operating temperature.
• Frequently check engine oil level. Add oil as needed. It is normal for oil consumption to be high during the break‑in period.
After the Break‑In Period
To help extend the life of your Mercury MerCruiser power package, follow these recommendations:
• Ensure that propeller allows the engine to operate at or near the top of the specified wide‑open‑throttle (WOT) RPM range.
Refer to Specifications and Maintenance.
• Operate the engine at 3/4 throttle or lower. Refrain from prolonged operation at WOT RPM.
• Change the engine oil and oil filter. Refer to Maintenance.

End of First Season Checkup

At the end of the first season of operation, contact an authorized Mercury MerCruiser dealer to discuss and/or perform scheduled
maintenance items. If you are in an area where the product is operated continuously, year‑round, you should contact your dealer
at the end of the first 100 hours of operation or once yearly, whichever occurs first.
90-8M0050539 MAY 2011
eng
Section 3 - On the Water
Page 61