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Old 06-11-2020, 05:50 AM   #23
FF
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Join Date: Oct 2007
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"It's still overpropping relative to the manufacturer specs, but depending on the engine, boat and usage patterns, it's not necessarily inappropriate."

Very true but the engine mfg prefers their system as it reduces warranty repairs on certain styles of vessel operation. And is much safer with a novice operating the vessel.

A boat that needs most or all of the engines rated HP and is usually operated at high power does well with the MFG rated RPM for the props. Sport fish , ski towing , police or military operations.

An engine that will be operated at a tiny fraction of the rared HP will live long and prosper producing the minor HP at far lower RPM.

Depending on the boat there can be a 300-500 RPM difference at cruise .

The lower RPM at cruise makes a big difference in noise on board , better fuel burn and engine life.

One early method of contemplating engine life was piston travel miles.

2100 RPM vs 1600 RPM , big difference in engine wear!

As is a 200HP engine being screamed to burn 2 GPH , for 30-35HP.
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