Watermann
Starmada Splash of the Year 2014
- Joined
- Jan 12, 2013
- Messages
- 13,822
Here's an article I thought was interesting with some very useful information. Thought I would pass it along.
Maximizing Engine Life
In addition to keeping the oil changed and all the other maintenance tasks up to date, there is another major factor in engine life: The RPMs that you use for continuous operation, where “continuous” is defined as operating for over one minute.
Assuming that the engine reaches the specified MAX RPM range, then the maximum RPMs for continuous operation should not exceed 80% of the actual maximum RPMs your boat achieves. For example, an engine with a specified 4400 to 4800 MAX RPMs range that maxes out at 4600 RPMs should have a maximum continuous operating RPMs of 80% of 4600 RPMs or 3680 RPMs. Dropping to 75% (3450) will increase engine life even further. Engines operated continuously at wide open RPMs typically exhibit engine life in the very low hundreds of hours. Engines operated at 80% or lower, especially fresh water cooled with 160-165 degree thermostat often exhibit life in the thousands of hours. Over propped engines, i.e., those that do not reach or exceed the lower end of the specified operating range, often have much shortened engine life even if run at 75 to 80% of maximum observed RPMS, with burnt exhaust valves being the usual failure mode.
Of course, it is entirely appropriate for you to run your engine wide open if you need to get out of a dangerous situation. Additionally, it is prudent to run your engine wide open several times a season as a “health check”. These run times should only be long enough to verify RPMs, oil pressure and water temp and smooth operation (no misfires), typically less than 30 seconds.
Maximizing Engine Life
In addition to keeping the oil changed and all the other maintenance tasks up to date, there is another major factor in engine life: The RPMs that you use for continuous operation, where “continuous” is defined as operating for over one minute.
Assuming that the engine reaches the specified MAX RPM range, then the maximum RPMs for continuous operation should not exceed 80% of the actual maximum RPMs your boat achieves. For example, an engine with a specified 4400 to 4800 MAX RPMs range that maxes out at 4600 RPMs should have a maximum continuous operating RPMs of 80% of 4600 RPMs or 3680 RPMs. Dropping to 75% (3450) will increase engine life even further. Engines operated continuously at wide open RPMs typically exhibit engine life in the very low hundreds of hours. Engines operated at 80% or lower, especially fresh water cooled with 160-165 degree thermostat often exhibit life in the thousands of hours. Over propped engines, i.e., those that do not reach or exceed the lower end of the specified operating range, often have much shortened engine life even if run at 75 to 80% of maximum observed RPMS, with burnt exhaust valves being the usual failure mode.
Of course, it is entirely appropriate for you to run your engine wide open if you need to get out of a dangerous situation. Additionally, it is prudent to run your engine wide open several times a season as a “health check”. These run times should only be long enough to verify RPMs, oil pressure and water temp and smooth operation (no misfires), typically less than 30 seconds.
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