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09-24-2017, 01:43 PM
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#1
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Member
City: Foster,ri
Join Date: May 2016
Posts: 19
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tachometers
I have twin Yanmars diesels on my 34 Pilot. The tachs are fine at idle. They top out at 2800. Checking the from the flywheel its showing the correct 3200-3300. Both tachs are off, Anyone have any suggestions on what to do ?
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09-24-2017, 03:47 PM
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#2
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,144
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There adjustments on many tachs. The first gets it in sync with whatever sending system you have, then a tiny potentiometer to fine tune them.
My old VDOs were no longer taking an adjustment so I replaced them with new Farias.
One easily adjusted, the other I couldnt seen to turn the potentiometer and with a little harder push, the screwdiver punch right through. Back to warranty.
So be careful trying to adjust any of them.
But first...check all your connections in the positive, negative and signal wires.
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09-24-2017, 04:22 PM
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#3
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,087
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Quote:
Originally Posted by Dennis G
I have twin Yanmars diesels on my 34 Pilot. The tachs are fine at idle. They top out at 2800. Checking the from the flywheel its showing the correct 3200-3300. Both tachs are off, Anyone have any suggestions on what to do ?
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Not electronic tachs?
Our boat came with analog tachs. They went south, so I had them rebuilt. They could be adjusted to be sort-of correct at one RPM level; for example, adjusted at 2000 RPM meant they were close, at 2000, but off some at 2600 and off at idle.
I replaced them with Aetna digital tachs. CruzPro also makes digital tachs, and maybe others do as well.
-Chris
__________________
Chesapeake Bay, USA
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09-24-2017, 04:23 PM
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#4
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Guru
City: Cape May, NJ
Vessel Name: Irish Lady
Vessel Model: Monk 36
Join Date: Dec 2007
Posts: 4,964
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Are they driven by the alternators with v-belts?
Belts tight?
__________________
Archie
Irish Lady
1984 Monk 36 Hull #46
Currently in Cape May, NJ
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09-24-2017, 07:32 PM
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#5
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Guru
City: Narragansett Bay
Vessel Model: Grand Banks 36 Classic #715
Join Date: Sep 2016
Posts: 1,857
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Are they Yanmar tachs? What model Yanmar engine?
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09-24-2017, 08:44 PM
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#6
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Senior Member
City: La Paz, BCS
Vessel Name: Ansedonia
Vessel Model: Californian/Carver 52CPMY
Join Date: Dec 2014
Posts: 379
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My last boat had digital tachs, and boy did they make it easy to set the RPMs the same for both motors. I may have to put them on my new boat too. Super accurate and easy to read.
Cheers, Bill
__________________
"There is simply nothing more worth while than messing around in boats."
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09-25-2017, 06:43 PM
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#7
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Guru
City: Full Time Cruising East Coast
Vessel Name: Meridian
Vessel Model: Krogen-42
Join Date: Aug 2011
Posts: 1,014
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Are these electronic tachs driven by the alternator or a sensor attach to the crank pulley?
__________________
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Terry
Meridian
KK-42097
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09-26-2017, 07:02 AM
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#8
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,087
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Quote:
Originally Posted by meridian
Are these electronic tachs driven by the alternator or a sensor attach to the crank pulley?
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Our Aetna digital tachs are driven by a magnetic sensor on the flywheel. (As were our original analog tachs.)
Think Aetna also has other models, though...
-Chris
__________________
Chesapeake Bay, USA
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10-18-2017, 09:57 AM
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#9
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Member
City: Foster,ri
Join Date: May 2016
Posts: 19
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Quote:
Originally Posted by High Wire
Are they driven by the alternators with v-belts?
Belts tight?
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Yes
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10-18-2017, 09:58 AM
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#10
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Member
City: Foster,ri
Join Date: May 2016
Posts: 19
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Quote:
Originally Posted by Easting
Are they Yanmar tachs? What model Yanmar engine?
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No Faria
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10-18-2017, 10:03 AM
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#11
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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Look at the back of the tachs and see if they have an adjustment screw.
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10-18-2017, 11:59 AM
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#12
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,087
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Quote:
Originally Posted by Dennis G
No Faria
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Quote:
Originally Posted by Ski in NC
Look at the back of the tachs and see if they have an adjustment screw.
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The Faria Chesapeake series tachs we had originally did have two adjustment screws, one for course dial-in, and then a second one for a finer adjustment.
That said, we could only get the "right" (-ish) at one RPM level, so setting at 2000 meant they weren't all that perfect at 650 (idle) and 2300 (WOT).
That partly drove our change to digital tachs.
-Chris
__________________
Chesapeake Bay, USA
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