[C320-list] FW: Re: Tach reads only 3000 rpm at full throttle
Jeff Church
jjemail at comcast.net
Wed Aug 29 20:49:21 PDT 2007
Bob,
I cleaned that connection last year and checked to make sure that the voltage was up to spec. I think it was OK, but it's worth the effort to check it again.
Thanks for the tip.
Jeff
----- Original Message -----
From: resloat at comcast.net
To: C320-List
Sent: Wednesday, August 29, 2007 8:42 PM
Subject: Re: [C320-list] FW: Re: Tach reads only 3000 rpm at full throttle
Jeff-My 320 hull 894 (2002) with the 3GM30F european version has the tach sensor near the top of the bell housing on the port side of the engine. The sensor measures the flywheel revolutions. A few years ago the tach started acting up and I found that the electrical connection at the sensor was slightly corroded even in fresh water Lake Michigan exposure. I cleaned off the spade and female connections, applied dielectric paste that the auto shops use for electrical connections to keep moisture out and the tach has performed without problem since.
The tach was not reading consistently low or high but wandering and only going up to about 2300 rpms when at full throttle.
Bob Sloat
Savannah
-------------- Original message --------------
From: "Jeff Church" <jjemail at comcast.net>
> 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"
>
> > 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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