[C320-list] Tachometer antics

[Magnuson's Time A Weigh]

Warren,
Thanks for the response and advice.  Since we live 500 miles from the boat, 
we live aboard for several weeks at a time, and do make extended trips on 
Superior.  Do you think that the alternator output is high enough to damage 
any of my onboard equipment or can I depend on the batteries to filter out 
any of the voltage fluctuations?  Can you give any pricing ideas of the two 
options you offered?  I am looking on the 320 site and not sure where to 
find the article you mentioned about the upgrade.   I will keep looking.

Any thoughts about why the tach seems to work just fine with the ignition 
switch turned off?   What effect would it have on the system to have the 
ignition switch in the off position with the engine running, other than the 
hour meter won't record the total run time?

Thanks again,
Gary Magnuson

----- Original Message ----- 
From: "Warren Updike" <wupdike at hotmail.com>
To: <C320-List at Catalina320.com>
Sent: Thursday, June 16, 2011 4:31 PM
Subject: Re: [C320-list] Tachometer antics


If you have the original alternator on your M30, then the regulator is 
internal to the alternator; and, the tach signal is derived directly from 
the alternator.  First, check all the wiring and connections on the back of 
the alternator all the way to the dash board.  Make sure all are clean and 
tight.  I made the attached wiring guide for my M30.  It may be the same for 
yours; but, don't rely on the wire colors as Catalina has been known to use 
whatever color is available, at least on the older boats.

Since your voltage is varying as well as the tach, my guess is that you have 
a problem with the alternator, either in the windings, brushes, or 
regulator.  You could probably take it to an auto shop to have it serviced; 
but, the cost might be better put toward a new alternator/regulator.

If you are a weekend sailor you may get away with the stock alternator; but, 
if a cruiser, you might want to consider an alternator/regulator upgrade.  I 
can send you the info I have on my upgrade where I basically followed the 
standard ver. 2, upgrade from on the site.  Be aware that the M30 doesn't 
use the US standard automotive mount for the alternator.  It's a gottc
Warren & Pattie Updike
1994 C320 #62 "Warr De Mar"


ha.

-----Original Message-----
From: Magnuson's Time A Weigh [mailto:gary.magnuson at frontier.com]
Sent: Thursday, June 16, 2011 2:55 PM
To: C320-List at Catalina320.com
Subject: [C320-list] Tachometer antics

On my 1995 hull 205, I have 484 hours on my Perkins M30, my tachometer has
started bouncing between 0 and what ever speed the engine is running. I just
tried the following here in the slip:  @2500 rpm, tachometer solid - volt
meter steady at about 14.8v
2000 rpm same,  1500 solid then bounces between 500 and 1500 while voltage
flutters between 14.8v and 15.3v
1000 rpm tachometer bounces 0 to 1000, voltage flutters around the 14.8v.
With ignition key turned off, engine still runs, but tachometer stays solid,
and volt meter flutters between 15v and 16v.
Turn key back on and the tachometer will bounce again.
I don't have an electrical schematic on board and being a Master of The
Obvious, I assume it is an alternator, regulator, transducer, or wiring
connection problem.
Will someone share their experience and solution.  This site is such a great
resource!!!

Thanks,
Gary Magnuson
320 #205