[C320-list] Am I slow under power?

[Karl Mielenhausen]

Here is a link to the speed curve for my 2000 C320, Yanmar 3GM, 15x9
3-bladed prop....
http://pages.suddenlink.net/kmielen/C320Docs/FuelEff.xls

You may be overpitched at 15x10 but not so much to explain all the rpm
loss. Other suggestions are excellent, especially checking the exhaust
elbow for blockage.
When you check the cable throw, make sure max at the pedestal
translates to max down on the engine.
You can also easily check to see that all 3 cylinders are
"contributing" by throwing each decompression lever (one at a time)
and watching and listening to what is happening.
We do have a Photo Tach available for loan from the C320IA toolbox
(free to dues paying members).
Let us know what you find out.

Karl

On Tue, Apr 17, 2012 at 7:21 AM, Nathan Mauch <nmauch at yahoo.com> wrote:
> I'm a pretty new C320 owner and I'm trying to figure out whether I have a tachometer issue or an throttle governor issue (3GM30F) on my '97 #453.   At full throttle, I make 5.3 knots in a dead calm, but my tach is only reading 2200 RPM, which I know is well below rated max.  However, I've seen my tach wander and I'm not convinced it's working properly.
> My question is, is 5.3 knots about right for this boat (15X10 prop) at full throttle, or is my tach corret and I'm not geting full RPM out of the engine?  Reading through previous posts, it sounds like I should be getting at or close to hull speed?
> Thanks,Nate,S/V Mistral