Hour meter question on a possible purchase

We're very interested in a particular Trawler but have a question about the hour meter readings.

It's a twin diesel vessel & one hour meter reads almost 500 hours more than the other.. 15xx vs 20xx.

This strikes me as pretty strange. I asked the broker about it & he told me it wasn't unusual & he often sees it because "even with the engine off, when the key is on the hour meter is running".

In every gas engine I've ever had the hour meter only cycles when it senses current from the spark plug cable so.. if not running = no hours recorded.

Is his statement likely to be true or false?

Should I be concerned about the large difference in the hours?

Thanks for any advice!

Hour meters can be notoriously inaccurate, a pair side by side can expose this, however, that spread is a bit large...
Wire broken for some time?
Did previous owner run on one engine for some reason?
Which alternator charges which battery bank?
Some inane reasoning by PO? "It's too noisy with the other one running..."?

And, if accidentally leaving the key on runs the hour meter, 500 hours is only 20 days?

Easy to even out for the OCD?

RB

Mine have a 600 hr difference. When I bought the boat, the stbd hour meter was inoperative. I found the loose wire and all is well again.

Mine only record when running and is indicated w/ an hourglass symbol on the tach.
You might see if there is any indicator when the engine is running & recording hrs - if so you should be able to see if it is on when key is on but engine not running.

Personally I find that explanation suspect - would an owner consistently leave key on w/ engine not running??

Another possibility might be owner ran on one engine in an effort to save fuel$

Probably half the boats I am on have a huge difference in HM readings. Many possible causes as listed above. Never a big deal.

I must confess. When I bought Magic the hour meters were different by 8 tenths of an hour. I can't understand why this bothered me. So, every time I start my engines, I start the lower reading engine first. When I shut down the engines, I shut down the lower reading engine last. Now after 5 years they are only 2 tenths apart. I think I may be OCD about this. I feel a lot better now. Thank you all for allowing me to share this.

hmason said:

I must confess. When I bought Magic the hour meters were different by 8 tenths of an hour. I can't understand why this bothered me. So, every time I start my engines, I start the lower reading engine first. When I shut down the engines, I shut down the lower reading engine last. Now after 5 years they are only 2 tenths apart. I think I may be OCD about this. I feel a lot better now. Thank you all for allowing me to share this.

Click to expand...

Howard,

When I lwant to see your picture, I know now just to look up OCD.

Hmmm I had the same answer from both the PO and the Broker... there was a 100 hour difference roughly. I took a photo of the meters before and after taking her out for an hour. Upon conclusion I showed them the pics and said, " port meter is broken dummy".....

My old cable driven tachs record hours slower at idle than at cruising rpm. Somewhere about 2000 rpm is registered as an hour. It takes a 2+ hours at idle to record an hour.
One answer on hour differences is trolling on one engine. A commercial fishing boat I owned had all the generators (pre-alternators), and hydraulic pump, wash down pump, on one engine. So that was the trolling engine. It also ran when battery charging at anchor. The po had overhauled the st'bd engine every ten years or so, but the port was original.
The generators were out of WWII bombers, about 8" in diameter, 12 and 32 volt, about 40 amps tops.

Hour meters have far shorter service lives than engines.

They are great for tracking the next oil change.

The vessels log book is a better info source.

Of the two engine hour meters one is currently about 500 hours greater then the other. That meter actually runs faster than the other so the difference increases over time. I used timed runs to evaluate the two hour meters to find which one was accurate. Since I determined which one is closer to accurate I use that for actual run times for both engines.

Marty.............................

I've actually checked hour meters against stop watches. Years ago I came up with rather large differences. On the more recent ones I've not found that. When we were chartering, we were on one boat that the hour meters weren't close. It took no time to tell why. One was supercharged, giving at least two hours for every hour.

It reminded me of a car rental years ago when mileage charges were common and overages very high. I went to return the car, having driven it 500 miles in one day as I rented it to get home when the airport I needed was basically fogged in. I walk up to the counter and said very nicely, "The odometer is not working correctly." Oh, the lady snapped at me as if I was trying to run a scam and said loudly and harshly, "The odometer is always right. We can only go by the miles recorded. That's the law." I responded, "The law? Well we'd hate to break the law. You may want to fix it though as it shows I drove 75 miles and I drove over 500." The look on her face.

Most people who run on one engine would even it up by working them alternately. So the "ran on one" more likely broker speak. Unless there was a major issue with the "unrun" engine.

Probably a loose wire at one point or one meter was replaced at some point.

I'm on my third meter for this boat. Two of them started operating oddly failing to run at all for periods of time or running initially and then quitting.
Boat is a single engine so no big deal as long as I'm aware they are goofing up.
But of course they do get replaced and the failure hours logged.

500 hrs may be a bit much but as suggested above there could be a good reason such as a slow or fast meter. Use a watch and time them. Maybe one is goofy.
These things are not high quality clocks.