[C320-list] Tachometer Problem

[Robert E. Sloat]

Jon-After corrosion around the plug was cleaned off, put dielectric paste on 
the plastic plugs and the electrical contacts to prevent further corrosion 
per the instructions on the Permatex instructions.
----- Original Message ----- 
From: "Jon Vez" <jonvez at comcast.net>
To: <C320-List at Catalina320.com>
Sent: Tuesday, July 07, 2009 6:58 PM
Subject: Re: [C320-list] Tachometer Problem


> Bob,
>
> One thing you can do to reduce corrosion around the engine is spray a 
> light
> coating of WD-40 over the entire engine (just keep it off the belts) and
> leave it there until Spring. When recommissioning just wipe the engine 
> down
> and lubricate the moving parts--you'll get a clean engine and keep 
> corrosion
> at bay--
>
> Regards,
>
> Jon Vez
> Solstice #582
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Robert E.
> Sloat
> Sent: Tuesday, July 07, 2009 9:42 AM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Tachometer Problem
>
> James-A few years ago I had a problem with the tachometer giving strange
> readings like yours on my hull 894 (2002) with a Yanmar 3GM30F.  The 
> problem
>
> was a little corrosion on the electrical plug connection near the magnetic
> pickup sensor for the tachometer.  The sensor is located near the flywheel
> at the top of the bell housing and the connection connects the tachometer 
> to
>
> the sensor.
>
> Since your problem seems to go away when the engine heats up it may be a
> combination of corrosion and moisture in the above electrical plug
> connection.
>
> My solution was to take the electrical plug connection near the tachometer
> sensor apart and clean it off and plug things back together.  No problem
> thereafter.  It is interesting that my boat was commissioned new in 2002 
> and
>
> has spent its entire life on fresh water Lake Michigan.  The corrosion on
> the plug occurred after only 3 seasons.
>
> Bob Sloat
> Savannah Hull 894
>
> ----- Original Message ----- 
> From: "Jamie Pett" <JPett at JP2ARCHITECTS.COM>
> To: <C320-List at Catalina320.com>
> Sent: Monday, July 06, 2009 4:08 PM
> Subject: [C320-list] (no subject)
>
>
>
>
> List - I had an odd tachometer anomaly this weekend and wondered if
> anyone can shed some light ?
>
>
>
> While motoring home I was monitoring the tach - always try to run at
> 3100 -3200 rpm which I understand is correct cruising for my motor-
> Yanmar engine.  The tach would be reading 3100, and with no noticeable
> change in the motor sound / speed etc. would drop to 2800 or so.  Once
> or twice it jumped up to like 3400, and I found myself throttling down,
> then my speed seemed slow.  ( To make matters worse, my speedo is not
> working, and sender is not fouled - guess the sending unit went bad ? So
> I am relying on gps for speed which jumps around a bit.)
>
>
>
> Does the tach. Run off the alternator ?  Could the problem be a belt ?
>
>
>
> Any thoughts on why this would happen ?
>
>
>
> After running for 20-30 minutes, I go the rpms settled at 3100 and
> stayed there steady all the way the home - 2 plus hours into Sunday's
> non-existent wind.
>
>
>
>
>
> Any insights appreciated -
>
>
>
>
>
> James Pett
>
> 'Bella Luna' #614
>
>
>
>
>