[C320-list] FW: Re: Tach reads only 3000 rpm at full throttle

Wed Aug 29 11:52:43 PDT 2007

Yes, but you can get Sinometer DT6234B for a few buck more and have an
accurate, reliable digital tachometer that will last for years---I use a few
times per year, but don't bother to adjust boat tach, just to know, i.e.,
that when boat reads 3200 it's really 3575.

Len Krane
AQUA5   #1070

On 8/29/07, Jeff Church <jjemail at comcast.net> wrote:
>
> Jim,
>
> I checked my RPM with an optical tach late last summer. The engine tach
> was reading low by about 400 RPM. This spring, when I intended to fix the
> problem, the tachs were in sync so I didn't make any adjustments. Last week
> it appeared that the engine noise and indicated RPM were not what I was used
> to. Sure enough, the optical tach shows that the engine tach is about 400
> RPM low again. Maybe engine box or alternator temp/output affects the tach
> sensor?
>
> I'd suggest checking the engine tach. You can get an optical tach for
> about $25 dollars at a hobby shop that sells RC helicopter and airplanes.
>
> Jeff
>   ----- Original Message -----
>   From: allan.field at comcast.net
>   To: C320-List
>   Sent: Wednesday, August 29, 2007 12:02 PM
>   Subject: Re: [C320-list] FW: Re: Tach reads only 3000 rpm at full
> throttle
>
>
>   Jim - I had Sea Shadow out of the water a few weeks ago after being in
> only about 7 months.  The prop was covered with barnacles.  This seems to be
> a particularly bad year for the little critters on the Bay.
>
>   The C320 Association has a Toolbox Loaner Program of which I am the
> custodian.  Linda and I probably will make at least one more trip to Oxford
> this Fall.  When we do, I will try to remember to bring the optical
> tachometer with me so that you can check your tach.  When I used it on Sea
> Shadow, I found that the boat tach was spot-on.  Otherwise, I can ship it
> over to you as part of the program.
>
>   Allan S. Field
>   Sea Shadow - #808
>   Columbia, MD
>
>   -------------- Original message --------------
>   From: "Jim and Stacey" <bredar-sewell at comcast.net>
>
>   > Thanks for the responses. I guess its time to grab the scraper and
> mask
>   > take a little dive. I'll report back. Jim Bredar, "Ranger", C320 #937
>   >
>   > -----Original Message-----
>   > From: c320-list-bounces at catalina320.com
>   > [mailto:c320-list-bounces at catalina320.com] On Behalf Of Karl
> Mielenhausen
>   > _/)
>   > Sent: Wednesday, August 29, 2007 11:21 AM
>   > To: C320-List at catalina320.com
>   > Subject: [C320-list] FW: Re: Tach reads only 3000 rpm at full throttle
>   >
>   >
>   > Jim,
>   >
>   > I concur with Chris. I had the exact same problem (could not develop
> 3600
>   > rpm). Also was running hotter than usual, but then again our river is
>   > currently 85F. Cleaning the prop of barnacles solved both problems.
>   >
>   >
>   >
>   > Karl Mielenhausen
>   >
>   > 2000 C320 Hull#690 "Silver Lining"
>   >
>   > New Bern, NC
>   >
>   > http://pages.suddenlink.net/kmielen/
>   >
>   > From: Chris Burti [mailto: clburti at gmail.com]
>   >
>   > To: c320-list at catalina320.com
>   >
>   > Date: Tue, 28 Aug 2007 22:28:46 -0400
>   >
>   > Subject: Re: [C320-list] Tach reads only 3000 rpm at full throttle
>   >
>   >
>   >
>   > Barnacles on the prop will do that fairly suddenly.On 8/28/07, Jim and
>   > Stacey wrote:> I have a 3GM in my 2003 C320,
>   > Hull no. 937. I have 300 hours on the> engine. Full throttle has
> always
>   > yielded a tach reading of just over 3600.> Yesterday I noticed that
> with the
>   > throttle full forward, the tach reads only> 3000 rpm. What gives? I
>   > don't have a keen enough ear to say whether> the engine sounds like it
> is
>   > actually at 3600 even though the tach says> 3000. Thoughts and
>   > suggestions appreciated.>> Jim Bredar, "Ranger", C320 No. 937, Oxford,
>   > Maryland>>>> -----Original Message-----> From:
>   > c320-list-bounces at catalina320.com>
>   > [mailto:c320-list-bounces at catalina320.com] On Behalf Of brucestanley>
> Sent:
>   > Tuesday, August 28, 2007 5:42 PM> To: C320-List> Subject: Re:
> [C320-list]
>   > calibration of my Tach>> Thanks Jeff> your explanation is
> appreciated.>>
>   > BruceStanley>> ----- Original Message -----> From: "Jeffrey Hare"
>   > > To:
>   > "'C320-List'" > Sent: Wednesday, August 29, 2007
>   > 12:24 AM> Subject: Re: [C320-list] calibration of my Tach>>> > The
> Yanmar
>   > 3GM series engines use a pickup on the flywheel to handle the> > Tach
>   > instead of the terminal on the alternator, so those with the 3GM> >
> engine>
>   > > don't usually have any re-calibration necessary when changing
>   > alternators.> > Given that you probably have the 3YM engine, it
> appears that
>   > they aren't> > using the flywheel pickup anymore in favor of the
> Tachometer
>   > terminal on> > the> > back of the Alternator like they do for the
> other
>   > non-yanmar engines on> > the> > C320.> >> > -Jeff> >> > -----Original
>   > Message-----> > From: c320-list-bounces at catalina320.com> >
>   > [mailto:c320-list-bounces at catalina320.com] On Behalf Of brucestanley>
> >
>   > Sent: Tuesday, August 28, 2007 3:14 AM> > To: C320-List;
>   > oldman1030 at hotmail.com; sthompson at toad.net> > Subject: [C320-list]
>   > calibration of my Tach> >> > Hi All> > re: the calibration of my Tach
> after
>   > I
>   > switched from the Hitachi 60Amp> > to an older Hitachi 80Amp. The
> 80amp Alt
>   > produced far higher Tach> > readings.> > This I solved by a terminal
> wiring
>   > alteration to the back of the Tach.> > This terminal was straight
> forward. I
>   > did this approx 14 mths ago.> > I am far from an electronics expert,
> but
>   > that is exactly what I did.> > I am a DIY advocate and love doing most
> of my
>   > own work on my Yacht.> > Parts I do not understand and parts I break.
> I
>   > still enjoy the journey.> >> > BruceStanley C320#1084> > Sydney
> Australia>
>   > >> > ----- Original Message -----> > From: "Chris Holt"
>   > > > To: "C320-List" > >
>   > Sent: Monday, August 27, 2007 9:48 PM> > Subject: Re: [C320-list] Club
>   > Racing the C320> >> >> >> That was what I had thought also. I also did
> not
>   > experience any> >> perceived> >> >> change of my tach readings after
> the
>   > installation. I have a 1997 with a> >> 3GM motor.> >>> >> Bruce, maybe
> you
>   > experienced this because of a
>   > different setup on the> >> 3YM> >> >> engines.> >>> >> Chris> >>> >>
> -----
>   > Original Message -----> >> From: "Scott Thompson" > >>
>   > To: "C320-List" > >> Sent: Sunday, August 26,
>   > 2007 7:09 PM> >> Subject: Re: [C320-list] Club Racing the C320> >>>
> >>>I
>   > don't know about the newer or older boats, but on my 1999 boat there
> is>
>   > >>>no need to recalibrate the tach when switching alternators. That's>
>   > >>>because on the Yanmar 3GM series of engines, the tachometer reading
>   > comes> >>>from a sensor in the flywheel housing that counts the
> flywheel
>   > teeth as> >>>they rotate past. In these engines tachometer calibration
> has
>   > nothing to> >>>do with the alternator.> >>>> >>> Scott> >>>> >>>
>   > brucestanley wrote:> >>>> Hi Stephen> >>>>> >>>> re Kiwi Prop and
> Engine
>   > Revs> >>>>> >>>> Fantastic Lady's 3YM30 cruises at 2100 to 2900 rpm.>
> >>>>
>   > Depending on tide/wind, this delivers 4+++ to 6+ knotts.> >>>>
> Occasionally
>   > I advance the Revs to 3000 and 3300rpm.>
>   > >>>> Sometimes to 3500++RPM for only a few minutes.> >>>> Revs are a
> bit of
>   > a lottery, in that one hopes the Catalina Tach is> >>>> calibrated
>   > accurately.> >>>> I am reasonably sure they are close to correct on
>   > Fantastic Lady.> >>>> Note: if you change your alternator you have to
> make a
>   > change at the> >>>> Tachometer.> >>>> I have an 80amp Hitach
> Alternator and
>   > have made this change.> >>>>> >>>> You must be able to Rev to 3600RPM
>   > (Yanmar's requirements).> >>>>> >>>> Hope this helps> >>>>> >>>> Bruce
>   > Stanley> >>>> C320 #1084 Fantastic Lady / Sydney Australia> >>>>> >>>>
>   > ----- Original Message ----- From: "Stephen Cox" > >>>> To:
>   > "'brucestanley'" > >>>> Sent: Thursday, August
>   > 23, 2007 1:30 PM> >>>> Subject: RE: [C320-list] Club Racing the C320>
> >>>>>
>   > >>>>> >>>>> Thanks Bruce.> >>>>>> >>>>> What revs can you get your
> motor up
>   > to with this prop?> >>>>>> >>>>> Stephen Cox> >>>>> Canberra> >>>>>>
> >>>>>>
>   > -----Original Message----->
>   > >>>>>> From: c320-list-bounces at catalina320.com> >>>>>>
>   > [mailto:c320-list-bounces at catalina320.com] On Behalf Of brucestanley>
> >>>>>>
>   > Sent: Thursday, 23 August 2007 8:20 AM> >>>>>> To: C320-List> >>>>>>
>   > Subject: Re: [C320-list] Club Racing the C320> >>>>>>> >>>>>> Stephen>
>   > >>>>>>> >>>>>> My Kiwi prop is 16.5"> >>>>>> and The factory has set
> the
>   > angle at 22 degrees.> >>>>>> This pitch setting of 22degrees is based
> on the
>   > engine you have.> >>>>>> Mine is the Yanmar 3YM30.> >>>>>>> >>>>>>
> Bruce
>   > Stanley> >>>>>> C320 #1084 Fantastic Lady / Sydney Australia> >>>>>>>
>   > >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>> >>> >> >> >> >> >>>>>-- Chris
>   > BurtiFarmville, NC
>   >
>   > _______________________________________________
>   >
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