Tachometer troubleshooting

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Talisman
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Tachometer troubleshooting

our website has a good article for troubleshooting a non-working fuel gauge.  I can't find a similar article for the tachometer.  Am I missing it?  If not anyone have one?

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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newguy
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Posts: 408

An oscilloscope or a frequency measuring DMM are the best tools to use as you're checking for pulses generated directly from your alternator stator or proxied by your voltage regulator.  Failing having one of these, then you might be able to roughly determine pulses by putting a voltmeter on the stator terminal of the tachometer, AC volts scale, and then varying the RPM of your engine.  I don't have a way right now to tell you what a good idle reading would be, but perhaps 5 volts.

  • Low voltage (<1 volt) suggest open wire or bad pulse generating
  • Good voltage, but not varying suggest bad pulse generating
  • Varying voltage but no needle deflection suggest bad tachometer

Nick Caballero
Retired C36/375IA Mk II Technical Editor

Talisman
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Posts: 244

Thanks. I'll try voltage approach

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

chic
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Joined: 2/13/08
Posts: 88

Has anyone re calibrated at tach on a 95 mkII. Is there an adjustment screw on back of tack?  Thx

William Miller
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Joined: 10/4/08
Posts: 294

I have a 1990 mk1 and there is a screw on the back to adjust I would think it would be the same for a mk2

Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

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newguy
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Hey Enrique,

Did you ever get this figured out?  If so, please share any details if you can.

Nick Caballero
Retired C36/375IA Mk II Technical Editor

Talisman
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Posts: 244

This will be a project for this Fall.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

Talisman
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Joined: 12/26/07
Posts: 244

Decided to deal with tachometer and fuel gauge issue this weekend.  Very frustrating.

I decided it was easy buying both gauges and a sending unit from CatalinaDirect and returning what I didnt need.

TACHOMETER - Disconnected the old and made all the connections to the new tachometer.  Same problem, hour counter and light works (so it is getting power) but tachometer doesn't.  Disconnected the wire from the Balmar Regulator and used a different test wire to the tach ignition post, similarly connected tach directly to Balmar alternator sending post, used test wire to connect alternator to regulator, used test wire to connect ground at the tachometer.  Could not make needle move.  By my limited electrical knowledge the only thing I haven't tested is if the sending unit of the alternator is not working or if more than one wire can be be bad.

FUEL GAUGE - After emptying out the port locker of years of stuff and opening the inspection port realized it only gave access to the fuel cutoff valve.  In order to get to the sending unit I would have to cut another inspection port on the locker bottom or remove the fuel tank.  I felt an additional inspection port would weaken the floor too much (already has two other large holes near by).  I'm too lazy to do all the disconnecting work in a confined area to remove the gas tank.  I will continue to live without a fuel gauge and use the engine hours calculation method which is probably more reliable anyway.

Any insights specially on the tachometer would be severely welcome.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

Talisman
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Joined: 12/26/07
Posts: 244

Maybe I should consider other options.  Maybe bypassing the Catalina designed systems with other options.  Has anyone installed a non-alternator sensing digital tachometer on the engine?  How about using one of the tank monitoring systems on the market to gauge fuel level?

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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LCBrandt
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Posts: 1282

The bottom of my cockpit locker has two openings, one for the fuel shutoff valve, the other to access the sender. This is the way it came from the factory.
 

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

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LCBrandt
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Posts: 1282

As for cutting another hole in the floor of the cockpit locker, I suggest you get a fiberglass guy to lay up glass over any unneeded holes. Then cut a hole directly over the sender. Use the sending/gauge system I describe in another thread and you will have reliable accurate fuel measuring. (In flat water the accuracy is astounding. I can predict to the tenth how much fuel I will need to load.)

Don't be lazy, Enrique. An accurate fuel measurement system is easily within reach.

Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
 

Talisman
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Posts: 244

I don't have unneeded holes that can be filled up in the locker.  There are two holes about 4 to 6 inches within a foot of each other.  One has hoses for an antisyphon system the other is for the fuel cutoff.  Another hole for the sender would have to be in between them and I'm afraid three large holes in a row like that would weaken the floor.  But if that is what you have I guess it's ok.  Larry let me know.  If you have pictures let me know

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

kakers
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Joined: 7/11/13
Posts: 43

I recently did that job on my 1995 boat. No hole for the sender so I cut a 4.5" dia. hole with hole saw and installed a 4" Beckson deck plate to match the existing one.

Just make sure to protect the sender wires and fuel lines when cutting.

Friend of mine has a 1999 and his came from the factory with two 4" deck plates.

 

Ken Akers
1995 C-36 MkII #1378  SR/FK  M35A
San Francisco Bay

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newguy
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Posts: 408
  • Engine off.
  • Disconnect ALL external charging sources (shore, solar, wind, etc)
  • Deplete your batteries down to 12.0 volts at rest.
  • Disconnect any wire connected to tach send
  • Using a NEW wire, connect your tach send directly to the stator terminal of the alternator.
  • Make sure your tach is suppled with power and ground.  It should light up.
  • Start your engine and throttle up to 1200 RPM.  Wait 1 minute.
  • What is your battery reading?  What does your tachometer indicate?

Nick Caballero
Retired C36/375IA Mk II Technical Editor

Talisman
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Joined: 12/26/07
Posts: 244

Problem was in the alternator.  The connection inside the unit was not attached to the post.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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