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turkvu
05-03-2008, 02:30 PM
Backstory: I had a new engine put into my '95 maristar 200 last spring. It rained a lot here so I probably only got about 20 hours on it last season. During the spring I installed a second battery and the BW isolator discussed in the dual battery thread.

Brought the boat into the shop to have a seal on the rudder box replaced. Two weeks later I got my boat back and noticed that on the service invoice it said the boat had 492 hours on it...saw this when I got home so I checked the boat and yep, the boat hours were at 492.

They had left the keys in the ignition and I think in the 'on' position. Would this cause the hours to keep running up?

The boat also would no longer start. I jumped it and ran around for about 20 minutes, stopped the engine and tried to start it back up again, no go. Had to jump it again to get it going.

What kind of damage did leaving it in the on position do? Is my battery a goner? Is some other part of the charging system gone (alternator?)?

Thanks for any help - I want to know what I'm talking about before I call the boat shop again.

justinglow
05-03-2008, 03:49 PM
How many days did they keep it there? If it had 20 hours on it when you left it there the key had to have been left on for about 19 days straight if my math is right.

As far as damaging anything unless your boat had "points" in the distributor you should be ok. The battery might be toast though...

Jerseydave
05-03-2008, 07:40 PM
If you have an electric fuel pump, the key on would have left it energized. Not sure if that's bad for the pump, maybe someone else can answer that.

I wonder what a scanner would read for hours now, 492 or 220?

Chas
05-03-2008, 07:51 PM
In my GM cars and trucks, the fuel pump runs for a few seconds before startup to pressurize the rails. Then is shuts down and waits until the key goes to start. The ECM runs it for a few seconds again, until the oil pressure switch closes, then it goes to automatic and cycles as the fuel pressure demands.

I don't know about the ECM used on marine applications, but I bet it is similar - the fuel pump would have run a few seconds and then stopped. The ECM and other electronics would have put a slow drain on the batteries - and the fact that they went over 400 hours before going dead is a testament to the great capacity that your system has! Wow!

I would bet that 20 minutes was simply not enough time to charge both batteries, and both would be dead if they were locked together by the relay while sitting with the key on.

I say charge them slowly and completely with an automatic charger, and then see how it goes.

Leaving a battery discharged is the worst thing you can do to it. I would worry more about how long they sat in that state than anything else.

coz
05-03-2008, 08:04 PM
When I bought my boat with 99 hrs, over 48 of those were because the previous owner left the radio on for 2 days after getting out of the water one day :rolleyes: good for me! :D

JBaker
05-03-2008, 09:09 PM
In my GM cars and trucks, the fuel pump runs for a few seconds before startup to pressurize the rails. Then is shuts down and waits until the key goes to start. The ECM runs it for a few seconds again, until the oil pressure switch closes, then it goes to automatic and cycles as the fuel pressure demands.

I don't know about the ECM used on marine applications, but I bet it is similar - the fuel pump would have run a few seconds and then stopped. The ECM and other electronics would have put a slow drain on the batteries - and the fact that they went over 400 hours before going dead is a testament to the great capacity that your system has! Wow!

I would bet that 20 minutes was simply not enough time to charge both batteries, and both would be dead if they were locked together by the relay while sitting with the key on.

I say charge them slowly and completely with an automatic charger, and then see how it goes.

Leaving a battery discharged is the worst thing you can do to it. I would worry more about how long they sat in that state than anything else.

Agreed. It could take a stock alternator (I'm assuming about 55 amps for that year) quite a while to fully charge that battery bank. You will probably be okay if you get them fully charged with an automatic charger unless they sat dead for an extended period of time.

I dunno about the hour meter thing. I'll be learning as this thread progresses.

turkvu
05-04-2008, 04:18 PM
Well - they had the boat for 13 days. So the math on the hours doesn't quite work. Especially since I doubt they even got to the boat for a few days. I would guess that it was in the 'on' position for 5 days tops. So accounting for the run up is very difficult.

JimN
05-04-2008, 05:25 PM
Don't charge the batteries with the alternator, use a charger. The alternator will get awfully hot with that load on it and heat kills everything. Why cause a problem that you don't need or want. Besides, Murphy's Law still exists.

The ECM will cycle the pump for a few seconds after the key is turned to ON, and stops. If the ECM sees 300 RPM or more, it operates the pump. If there's no tach signal, it won't.

The Hobbs meter will run as long as the key is on but the ECM records actual run time.
If you have any way to prove the meter indicates a vastly different number from what it did when you took it in, they're on the hook for whatever it needs. Make sure there's no current drain before you take it in, though.

Why did they have it for 13 days?

I would never leave a vehicle for service and make it possible for the stereo to operate. If it sounds really good, it may not when you get it back. I have heard of people getting cars back with blown speakers, missing equipment and all kinds of other nightmares.

Bruce
05-04-2008, 06:46 PM
I am mechanically challenged so I am reluctant to comment but, it is my understanding hrs don't show on the gauge unless the engine is running and it is throttled up to ? rpm.(don't remember the #)Maybe I misunderstood and that only applies to ECM hrs. but I have sure heard/read that somewhere. (but as I say to me a wheelbarrow is machinery!)

TX.X-30 fan
05-04-2008, 07:44 PM
I dunno about the hour meter thing. I'll be learning as this thread progresses.




Hold the bus!!!!!!!! Who the hell logged in as JBaker. :mad:




8p

JimN
05-04-2008, 08:53 PM
Being a '95, the Hobbs meter advances any time it gets voltage. The ECM shows the true run time, but if it's replaced, the boat owner won't know how many hours are on the motor unless whoever installs it makes a note of it and informs the boat owner.

Chas
05-04-2008, 10:02 PM
My old S&S doesn't have an hour meter, but I am adding one. I am going to add an oil pressure switch and wire it in to that so it only advances when the engine is running.

OK - so it will only advance when the engine is running with oil pressure...:)

JimN
05-04-2008, 10:19 PM
If the oil pressure switch provides continuity with pressure, then yes, it will only advance the Hobbs meter when the engine runs. The switch won't be able to handle much current, so the best way to wire it is so the oil pressure switch latches a Bosch-style relay, and the relay will supply the current to the meter. If you need a diagram, let me know.

Chas
05-04-2008, 10:31 PM
I have the meter already, but I didn't think it would draw much amperage - but you have me thinking - thanks Jim!

I'll see if I can find some current ratings for the meter, if not I'll clamp an amprobe on the lead.

Do you suppose I can find an amp rating for an oil pressure switch?

turkvu
05-05-2008, 12:09 AM
The ECM will cycle the pump for a few seconds after the key is turned to ON, and stops. If the ECM sees 300 RPM or more, it operates the pump. If there's no tach signal, it won't.

The Hobbs meter will run as long as the key is on but the ECM records actual run time.
If you have any way to prove the meter indicates a vastly different number from what it did when you took it in, they're on the hook for whatever it needs. Make sure there's no current drain before you take it in, though.

Why did they have it for 13 days?


Not sure I have any way to prove it. How do get the hours from the ECM?

Well, the shop I took it to had a week long backlog for service, and for some reason doesn't allow you to just call ahead and tell them it'll be there in a week. Then it took me a few days to get over there to pick it up.

JimN
05-05-2008, 12:36 AM
chas- I would imagine that someone, somewhere has a current rating for one but since it's just providing the ground reference for the gauge, I seriously doubt it will handle much more than 1/2A. That being the case, a relay is a really easy way to deal with more current, since the coil draws about 150mA.

You don't need a clamp and at such a low level, it's probably not going to be very accurate, anyway. I would just connect a multi-meter in series to measure the current as long as the meter can handle more than a few amps.

JimN
05-05-2008, 12:40 AM
turkvu- about the only way to see the run rime is by connecting a diagnostic computer, which the dealer should have. If there's any kind of dispute about whether the key was left on or not, they should really volunteer to hook it up, as a measure of goodwill. Their job is to take care of boat owners' problems, not cause them, although I'm not jumping to any conclusions. For the little time it takes, they can also give you a printout or handwritten sheet with the data on it, for your records. They should be checking the data when a performance issue is addressed, anyway.