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04-11-2011, 10:29
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#1
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Registered User
Join Date: Dec 2010
Location: San Francisco
Boat: O'Day 37 Center Cockpit "Namaste"
Posts: 85
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Discrepancy Between Engine Hour Meter and Reality
Wondering if anyone has any comments or advice re: I've noticed that my hour meter doesn't jive with reality; during a trip up the Sacramento Delta--about a 11 hour trip from San Francisco according to my watch--the engine hour meter logged around 20 hours. Engine is a 1995 Yanmar 3GM with about 400 hours, runs well. (The hour meter glass is cracked, so it's possible that the meter might be slightly whacked, but it seems to work smoothly.
I'm not a mechanic, so perhaps there's a purpose to this. Or, I've entered into a time warp or another dimension--time does seem to slow down in the Delta.
Thanks, and cheers,
Larry
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04-11-2011, 10:32
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#2
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Registered User
Join Date: Apr 2004
Location: Toronto
Boat: CS36Merlin, "La Belle Aurore"
Posts: 7,557
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Re: Discrepancy with Engine Hour Meter and Reality
were you motoring against the current?
__________________
Rick I
Toronto in summer, Bahamas in winter.
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04-11-2011, 11:04
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#3
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,558
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Vasco
were you motoring against the current? 
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In an 11 hour trip there one would have both favorable and unfavorable currents for that is nearly a full tidal cycle... but what the hell difference would it make?
For the OP: you might just try running the engine for an hour or so and check it directly against a watch. That would be long enough to show the nearly 2:1 discrepancy you describe. The other obvious thing would be that the "ignition" switch was left on whilst the engine was not running. On many setups the hour meter starts recording as soon as the switch is turned on and not when the engine actually starts. Similarly when shutting down...
Cheers,
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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04-11-2011, 11:07
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#4
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Registered User
Join Date: Apr 2004
Location: Toronto
Boat: CS36Merlin, "La Belle Aurore"
Posts: 7,557
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Jim Cate
In an 11 hour trip there one would have both favorable and unfavorable currents for that is nearly a full tidal cycle... but what the hell difference would it make?
Jim
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Lighten up Jim, it's a silly joke. Current would not make any difference as far as inaccuracy in the hour meter. The 3GM has a mechanical hour meter, it's obviously faulty.
__________________
Rick I
Toronto in summer, Bahamas in winter.
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04-11-2011, 11:18
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#5
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,558
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Vasco
Lighten up Jim, it's a silly joke. Current would not make any difference as far as inaccuracy in the hour meter. The 3GM has a mechanical hour meter, it's obviously faulty.
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ooops!
I hear my faulty sense of humour alarm sounding... sorry 'bout that.
Cheers,
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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04-11-2011, 11:22
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#6
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Registered User
Join Date: Apr 2004
Location: Toronto
Boat: CS36Merlin, "La Belle Aurore"
Posts: 7,557
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Jim Cate
ooops!
I hear my faulty sense of humour alarm sounding... sorry 'bout that.
Cheers,
Jim
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No problem, most folks don't get my jokes. I must have watched too much Monty Python.
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Rick I
Toronto in summer, Bahamas in winter.
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04-11-2011, 11:48
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#7
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,763
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Re: Discrepancy with Engine Hour Meter and Reality
I had an hour meter that ticked off 1/10 hour every couple of minutes. Not sure what the problem was. Is the speed of these things voltage dependent? At any rate I would just replace it.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard
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04-11-2011, 12:56
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#8
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Registered User
Join Date: Oct 2007
Location: Hollywood, Fl.
Boat: FP Athena 38' Poerava
Posts: 4,028
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Vasco
No problem, most folks don't get my jokes. I must have watched too much Monty Python.
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I got the joke and thought it funny.
But in all seriousness if the OP ran the motor twice as hard at twice the rpms that could account for double the hours. Geesh, it's simple math.
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04-11-2011, 13:05
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#9
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cat herder, extreme blacksheep
Join Date: Jul 2008
Location: furycame alley , tropics, mexico for now
Boat: 1976 FORMOSA yankee clipper 41
Posts: 18,967
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Re: Discrepancy with Engine Hour Meter and Reality
i try really hard to log the hours i use engine on a log book--sometimes i forget--but i kinda know how many hours i have--i havent a hobbes meter-so it wont go bad on me..
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04-11-2011, 13:17
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#10
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Registered User
Join Date: Aug 2010
Location: Central California
Boat: M/V Carquinez Coot
Posts: 3,782
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Cheechako
I had an hour meter that ticked off 1/10 hour every couple of minutes. Not sure what the problem was. Is the speed of these things voltage dependent? At any rate I would just replace it.
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Since my engine-hour meter reading is part of the tachometer, would I be wrong to assume that the engine hours are a function of the engine's revolutions?
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04-11-2011, 13:23
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#11
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Registered User
Join Date: Apr 2004
Location: Toronto
Boat: CS36Merlin, "La Belle Aurore"
Posts: 7,557
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by markpierce
Since my engine-hour meter reading is part of the tachometer, would I be wrong to assume that the engine hours are a function of the engine's revolutions?

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Yes. It has nothing to do with the revs. It's just a counter that starts when the ignition is turned on.
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Rick I
Toronto in summer, Bahamas in winter.
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04-11-2011, 13:28
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#12
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Senior Cruiser

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 51,775
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Re: Discrepancy with Engine Hour Meter and Reality
Quote:
Originally Posted by Vasco
Yes. It has nothing to do with the revs.
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Indeed.
Your Hour-meter is just an electric clock, which runs when it has electrical power (ignition 'on').
See ➥ http://www.egauges.com/pdf/vdo/0-515-012-037.pdf
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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04-11-2011, 14:02
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#13
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CLOD
Join Date: Jul 2007
Location: being planted in Jacksonville Fl
Boat: none
Posts: 20,813
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Re: Discrepancy with Engine Hour Meter and Reality
[QUOTE=Jim Cate;810640. The other obvious thing would be that the "ignition" switch was left on whilst the engine was not running. On many setups the hour meter starts recording as soon as the switch is turned on and not when the engine actually starts. Similarly when shutting down...
Cheers,
Jim[/QUOTE]
And if this was the cause (which would cause the meter to keep running) you need to check your low oil pressure alarm to be sure it is on and working.
__________________
Don't ask a bunch of unknown forum people if it is OK to do something on YOUR boat. It is your boat, do what you want!
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04-11-2011, 14:06
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#14
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Registered User
Join Date: Aug 2010
Location: Central California
Boat: M/V Carquinez Coot
Posts: 3,782
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Re: Discrepancy with Engine Hour Meter and Reality
My alarm goes on whenever the key is turned on but the engine isn't running. So, it goes on when starting and stopping the engine.
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04-11-2011, 15:27
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#15
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Registered User
Join Date: Dec 2010
Location: San Francisco
Boat: O'Day 37 Center Cockpit "Namaste"
Posts: 85
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Re: Discrepancy with Engine Hour Meter and Reality
Ok...so thanks for all of the input. It sounds as if the hour meter is just an electric clock based on the "engine on" switch. (I did not have the key off.) The meter doesn't have a mechanical cable to it that indicate otherwise. (As I said, the glass is cracked, so perhaps it is broken.) This is sort of good news, as it means my Yanmar has less hours than presumed. I do keep a log of hours, both regular clock based and engine hour based, so I can figure it out. Also, fairly sure the oil and temp lights are working correctly; I recently purchased meters for those, and one of these rainy days they'll get installed.
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