Discrepancy Between Engine Hour Meter and Reality

[lorenzo123]

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

[Vasco]

were you motoring against the current?

[Jim Cate]

Originally Posted by Vasco

were you motoring against the current?

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

[Vasco]

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

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.

[Jim Cate]

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.

ooops!

I hear my faulty sense of humour alarm sounding... sorry 'bout that.

Cheers,

Jim

[Vasco]

Originally Posted by Jim Cate

ooops!

I hear my faulty sense of humour alarm sounding... sorry 'bout that.

Cheers,

Jim

No problem, most folks don't get my jokes. I must have watched too much Monty Python.

[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.

[Tellie]

Originally Posted by Vasco

No problem, most folks don't get my jokes. I must have watched too much Monty Python.

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.

[zeehag]

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..

[markpierce]

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.

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?

[Vasco]

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?

Yes. It has nothing to do with the revs. It's just a counter that starts when the ignition is turned on.

[GordMay]

Originally Posted by Vasco

Yes. It has nothing to do with the revs.

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

[sailorboy1]

[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.

[markpierce]

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.

[lorenzo123]

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.