[C320-list] Engine RPM

[Warren]

Donald, I don't have all my docs handy; and the answer to your question 
may depend on things such as below-the-water conditions of hull, shaft, and 
prop.  For what it's worth, I think the max rated rpm of this engine is 
3.600.  Recommended max cruising rpm is 80% of that, or 2880rpm.  I 
typically cruise at 2600-2700 for long periods of time, rarely under 2500.  
I have had occasion to push over 3000; but, experience overheating after 
some time at this level.  At 2600, I'll have speeds of 5/5 to 6 kts 
typical.  Worth noting is that a couple of years ago I used an optical tach 
to calibrate my tachometer.  If you haven't calibrated yours, you might 
want to do this.  The tool loner program such a tool for your use.
Warren Updike, Hull #62

On Saturday, August 4, 2012 10:47:42 AM UTC-4, Donald Poole wrote:

> I have a Perkins M30 and a three blade 15X9 prop. Anyone have a similar 
> set 
> up and if so what have you found to be the optimum RPM above which you get 
> no boat speed improvement. It's looking like it's somewhere in the 21,000 
> to 25,000 RPM but I have not had enough run time yet to determine. 
>