[C320-list] Normal Performance Limits?

[Monte B.]

I have owned mine since new in 1999 and have accumulated about 750 engine
hours. For most of those hours I ran it very conservatively at 2500 RPM's
and not quite 6 knots. After reading the posts about exhaust elbow coking, I
pulled my ex. mixing elbow and found it to be quite coked but nowhere near
plugged as some have reported. I now run it at 3000 and it is actually
smoother at that RPM and obviously faster at the expense of a higher fuel
burn. I think Yanmar calls for max RPM of 3600 and max continuous of 3400. I
have come to believe that diesel's like to work near their design load limit
and at lower RPM and load tend to run rich and the lower exhaust gas
temperatures cause exhaust component coking. I don't know how they avoid
this with automobile diesel engines but they are not designed to be
continuous duty cycle as these small industrial and marine engines are.

Monte
Laima #620

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Jack McDonough
Sent: Saturday, October 04, 2008 7:37 AM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Normal Performance Limits?

I've had my 320 since it was new in 2003 and I have never run my Yanmar 27 
much more than 2600 or, rarely, 2800 rpm. With a three-blade prop, I'm 
probably doing about 6 knots over the ground. My recollection is that those 
rpms are about what the engine mounting plate and the Catalina manual 
suggest. Am I right or wrong?

Jack
#947




----- Original Message ----- 
From: "Monte B." <mjbc60 at sbcglobal.net>
To: <C320-List at Catalina320.com>
Sent: Friday, October 03, 2008 8:46 PM
Subject: Re: [C320-list] Normal Performance Limits?


>I didn't disagree with Rod. I reiterate, these instrument systems (tachs)
> are poorly calibrated and if you normally run your engine at a 
> conservative
> RPM and then firewall it you may expect to see smoke just from the higher
> exhaust gas temp burning combustion deposits out of the exhaust system. 
> That
> having been said I would agree that prop pitch controls max. RPM.
>
> Monte
> Laima #620
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of
> joe at dolphinmortgage.com
> Sent: Friday, October 03, 2008 8:32 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Normal Performance Limits?
>
> I agree with Rod, low RPM and black smoke with clean bottom & Prop means 
> it
> is overpitched. Should run at 3600 RPM at Max throttle.
> Joe Barrett
>
> -----Original Message-----
> From: Monte B. [mailto:mjbc60 at sbcglobal.net]
> Sent: Friday, October 3, 2008 08:53 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Normal Performance Limits?
>
> These boats also have notoriously inaccurate tach,s, something else to
> check. Monte Laima #620 -----Original Message----- From:
> c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Rod Boer 
> Sent:
> Friday, October 03, 2008 7:12 PM To: C320-List at Catalina320.com Subject: 
> Re:
> [C320-list] Normal Performance Limits? It sounds to me that you are over
> propped. You should be able to get up to 3400 RPM. Can you adjust the 
> pitch
> on the Kiwi? If so, just reduce the pitch and you should be able to get up
> to the full RPM Rod Boer Odyssey, #688 -----Original Message----- From:
> c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Amirault
> Family - S&B Sent: Friday, October 03, 2008 7:01 PM To:
> c320-list at catalina320.com Subject: [C320-list] Normal Performance Limits? 
> I
> had my boat on the water yesterday afternoon for likely the last sail of 
> the
> season. Although the wind was 15-20 knots on departure it had dropped to
> near nil by the time the crew decided to head for home. To ensure we 
> arrived
> at the dock before dark I slowly pushed the throttle to maximum. On still
> water this gave me revs at 2900, knots at 6.75 and plenty of black smoke. 
> On
> easing the throttle back to 2500 revs I was able to maintain 6 knots and
> eliminate the smoke. I have a Yanmar 3GM30, a clean bottom and a Kiwi 
> prop.
> Is this approximately normal? Brian Amirault #797 Waltzing Bear, too
>